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ZJ Hatch conversion - updating to lift glass style

25K views 11 replies 7 participants last post by  Bhfear 
#1 ·
OK, here goes – my first writeup. This is written for people that might not have much experience in this kind of thing so it may be oversimplified at times.
It’s a direct bolt on swap but requires a few wires to be moved and two or three added to make it all work correctly. This wiring work is fairly easy.
My conversion was a 96 Laredo lift glass hatch onto a 93 LTD. I used my 98 LTD to compare wiring/function/power distribution etc.
What I found out from that is documented here and will save you a lot of time and effort.

If you are reading this solely for info on how to R&R the lift gate (hatch) or replace it with the same type – skip to the removal section.

To do the conversion you will need the ENTIRE lift glass hatch intact from the interior trim to the wiper motor and arm. About the only interchangeable parts are the struts, lock/unlock motor, limit switch and the lower latch. Fixed glass hatch wiring harness won’t work on the lift glass hatch without a whole bunch of modification, if at all. Fixed glass wiper motor will work but will not park or stop as intended when the hatch or glass opens.
This swap is based on scavenging a few wires from the harness on your old hatch. If you don’t have your original wiring you will need to buy some suitable gauge wire or grab extra from the donor Jeep like I did but certain less essential connections will be hard to duplicate without the proper pins.
There are a few tradeoffs you can make as far as wiring and function if you don’t need all functions but it’s pretty easy to get to 100%. I’ll discuss what will and won’t work with/without various wire swaps further on.

This is broken down into five sections: Comments, Hatch R&R, Mandatory Wiring, Providing for window release button and interior lighting, Wiper motor problems w/ link to a post on rebuilding the motor.

COMMENTS:
A) Abbreviations - PLEASE TAKE NOTE - Besides the standard Jeep abbreviations I’ve made up a few of my own.
FXD and LFT for the type of hatch or Jeep. FXD – 93 to 95 Fixed glass type. LFT – 96 to 98 Lift glass type.
BC1 to BC6 and HCL or HCR for the Body Connectors/Hatch Connectors– Six body wiring connectors into two hatch wiring connectors in the top of the hatch
HCL and BC1, 2 and 3 are on the left bundle. HCR and BC4, 5 and 6 are on the right bundle.
HOLS – Hatch open limit switch. This switch doesn’t actually limit anything. This is the factory designation for the switch on the hatch or glass that operates the interior lights or VIC Lift Gate open indication
HAT – Hot at All Times - wiring that is live without the key being on.
LGOI – Lift gate open indication – The message that shows on the VIC.

B) The wiring & connector designations for this writeup are described left to right facing the Jeep with the hatch open. The designations will read upside down if you are looking at the hatch off the vehicle.

C) My conversion required swapping two existing wires to different slots in the BCs (mandatory) and, if you want all functions - adding one hot wire on the body side that runs to the body connector and two wires into the hatch harness with two splices further down.

D) This is what you will end up with. Everything works as per Jeep specs.
1. License plate lights and brake lights.
2. Wiper works as intended – On, Delay, Squirt and it parks when window or hatch opens.
3. Heated glass works.
4. Hatch locks/unlocks with the doors as intended. (With key on or off)
5. Glass open button for the lift glass works as intended. (With key on or off but only when the system is unlocked, as intended)
6. I haven’t checked the alarm system since I have a bad driver’s door switch but that should work as intended too.
7. Interior lights work with the hatch or glass open.
8. LIFTGATE OPEN indication works on the VIC. BTW – There is no separate “LIFTGLASS OPEN” indication on any year ZJ. The VIC will only say “LIFTGATE OPEN” for the glass or the hatch

E) Two important things to take into account when you test or troubleshoot the systems after installation:
1) The LFT wiper motor is designed to park immediately if the hatch or glass opens while it is wiping. It does NOT restart when the gate is closed. Wiper switch or ignition must be cycled off/on for it to resume working. That is normal operation and is internal to the motor. The FXD wiper motor will not do this if used on the FLP.
To test or troubleshoot the wiper motor function with the hatch open you must push the latch mechanism all the way to the closed position with a screwdriver.
The latch is not spring loaded to open so you must also use the screwdriver to pull the latch open while you lift the handle or it will make that ugly noise when you try to shut it 


2) The "cargo lamps" above the hatch have a disable feature activated/deactivated by pushing on the light cover.
The interior lights won't come on when the hatch opens if you hit the disable. Check this if the interior lights don’t come on when the hatch or glass is open. If you use a newer model ZJ to make wiring/powered wire comparisons, remember that the interior lights may time out about 60 or 30 seconds after the hatch opens.

F) There were changes to the wire colors between 96 and 98 but the functions are the same. If you have a 94 or 95 it couldn’t hurt to grab a test light or meter to confirm the wiring works like my 93.

G) If you find any differences from what I’ve listed here, please PM me so I can update this writeup.

LIFTGATE REMOVAL/REINSTALL:

BODY INTERIOR TRIM:
The Body top interior trim with the vents and cargo light needs to come off so you can disconnect the washer hose and for access to the one live wire you will need to tap into. Also, it needs to come off for access to the bolts for the body side of the hinge if you need to replace the hinges or adjust the hatch. (See note re washer hose if you are doing a replacement and not a conversion)
Four screws hold this trim panel on. Two are visible and two are under the cargo lamp. To remove the light lens pry GENTLY at the bottom to dislodge the hinge (not the top) then it will drop out. Same deal when reinstalling the light cover. Insert the top first, line up the hinges and snap it in. Otherwise it will get stuck under the trim.
There are metal clips that hold the trim in place once the screws are out. Pull the trim straight down or pry a bit with a screwdriver to dislodge them. If the clips break, the screws will still hold the trim on.

HATCH INTERIOR TRIM:
On your FXD the hatch interior trim panel is one piece and must be entirely removed to get to the connectors:
On the LFT only the top section of the hatch trim needs to come off for the hatch removal but at some point you might want to remove the lower section so it doesn’t get damaged during transportation.
The interior trim is pretty straight forward. Phillips screws all over the place but remember, on both types of hatches there are two that are fairly well hidden inside the lower corners of the carpeted section of the hatch panel trim. Feel around for them. Once the trim screws are out, it’s held in by the usual plastic push pins that love to break. Suitable replacements can be found at auto parts stores.

ELECTRICAL and HOSE CONNECTIONS:


There are two separate wiring bundles that join the body and the lift gate through connectors in the top of the hatch.
HCL and BC1, 2 and 3 are on the left bundle. HCR and BC4, 5 and 6 are on the right bundle. Six body wiring connectors into two hatch wiring connectors.

Once the panel is off you will see two identical black connectors at the top of the hatch, the HCs. Unscrew two Phillips on each one, lift the connectors towards the glass very slightly and pull it back gently. The mounting ears like to partially crack but that’s no big deal. Enough remains to attach the connectors securely. If you want to glue them back together it’s best to wait until you are reinstalling them as the wiring fights against it being held together while it dries.
Disconnect the six body connectors (3 each side) from the two hatch connectors. Once you have the six connectors disconnected, detach the accordion rubber from the hatch, fish the body wiring and connectors out of the hatch and push them down out of the way.
BTW - The six position connectors (BC3 and BC6) are a bit of a pain in the neck to remove, be patient.

Two other options if the donor vehicle is junk and you’re in a hurry: You could cut through the wiring at the “accordion rubbers” that join it to the body. Or – cut it somewhere in the interior of the donor vehicle and pull it through. There are some pins that are good to have and extra wiring is never a bad idea but you better check with the owner of the vehicle before you start cutting the harnesses.

WASHER HOSE:
The hose from the body joins the hatch hose via a plastic inline connector/one way check valve located under the Body upper trim panel right next to the cargo lamp. Disconnect this, remove the rubber grommet that the hose runs through and pull it out of the body.
NOTE: If you are doing a straight replacement with a similar hatch and not doing the conversion, I suppose you could skip removing the cargo light trim panel by removing the grommet on the body or the hatch and pulling the hose out enough to cut it and join it to the hose from the new hatch with an inline connector from an auto parts store. Just make sure you leave enough hose to work with!!
This new connector should then be added “behind” either grommet so it will be situated inside the body or hatch where there will be no wear or flexing, not situated between the hatch and the body.

THE HATCH:
The hatch is fairly heavy and very awkward to support while trying to remove or install it alone. My 93 hatch stripped of everything except the glass weighs in at 48 lbs. I’m guessing it would weigh 55 - 60 or more complete and I believe the LFT hatch is 5 or 10 lbs heavier – so get a helper if possible.
Put a good heavy blanket, towels or cardboard etc between the roof and the hatch and between the hatch and the hinges to prevent scratches or damage. Padding for where you are going to set it down too.

Once you have the connectors and hose out of the way disconnect the struts from the body and secure them out of the way with rope, wire or tape etc or remove them completely. If you have to remove the struts the bolts are a type of external Torx, not sure of the size. You might be able to find a regular 12 point socket that will work. If the struts are junk this might be a good time to remove them.

HINGES:
Two choices, six ½ inch head bolts on the body side of the hinge, accessed under the interior trim panel or the four T40 Torx bolts you can see with the hatch open. Unless you happen to have bad hinges it’s much easier to work with the four Torx bolts.

A quick word about that PITA rubber insulation in the hatch: It is also known as the “water excluder”. Some water does find its way inside the hatch. The water excluder is designed to direct the water to the bottom of the hatch so it can escape into the hatch jam rather than finding its way into the interior or dripping on your head when you open the hatch. It needs to be lifted up very slowly and carefully from the spots were it is glued to the hatch or it will tear or stretch. Some type of plastic scraper could be used to push through the glue.
If you don’t have one or if yours is too damaged to reuse, cut a piece of heavy duty plastic to size and tape or glue that in place once all wiring work is done and the functions have been tested.

Lock cylinder: Very carefully pry the black plastic switch off the back of the lock cylinder. That is the alarm switch. Next you have to pop the rod out of its plastic holder and remove it. Then remove the horseshow type clip that holds the cylinder in and remove/swap your lock cylinder into the new hatch.
If your hatch doesn’t open well, adjust the threaded rod. Try moving the threaded rod up for a shorter throw.

Installation is the same but backwards :) The Torx bolts provide up and down adjustment, the six 1/2 head bolts provide in and out adjustment. Leave the hatch interior panel off until you have checked the function of all systems.

MANDATORY WIRING WORK:
Check the connector diagram I made for my three hatches. (This is looking at the rear of the black connectors as you would see it when the trim is removed – upside down) You should be able to print it out. If there are any differences from these make note of it on the printout or make your own diagram for your reference. I used the same slot designation as the Haynes manual. No idea of this corresponds to Jeep designations.

BC1 and BC4 are identical three position connectors – 3 used on BC1, 2 used on BC4.
BC2 and BC5 are identical two position connectors – 1 used on each.
BC3 and BC6 are identical six position connectors – 3 used on BC3, 3 used on LFT BC6, 4 used on FXD BC6.

The ZJs have two main wires that power a lot of the important hatch functions like the Lock/Unlock system and the Wiper Motor - one each at BC1 and BC4. On the LFT ZJ they are powered at all times. On the FXD ZJ they are only live when the ignition is on. As far as functional differences, this only affects how/when the window release button operates. That is covered further on.
These wires are both Pink/Black on the LFT ZJ. On the FXD ZJ you have Pink/Black at BC1 and Brown/Pink at BC4.
There were subtle differences between 96 and 98 FLP wire colors but the functions are the same. If you have a 94 or 95 it couldn’t hurt to grab a test light or meter to confirm the wiring works like the 93 I describe here.

Some quick connector tips.
On the connectors and especially on the pins – push them in or together first to relieve the pressure while you unclip them, then pull them out or apart. On the connectors - remove the plastic “pin retainer” usually red or yellow, from the face of the connector and the rubber insert in the back of the connector if it has one. The smaller pins on the six position connector are a pain in the neck. To push the plastic retainers back you will need something very small like a fine jeweler’s screwdriver. If you don’t have that try a very stiff wire or paper clip etc. to push up the tiny piece of plastic that holds the pin in the connector. You can actually use a round wooden toothpick but they usually only last for one or two pin removals.
ALL PINS LOAD FROM THE BACK OF THE CONNECTOR.

Two mandatory swaps: FYI – Much easier to do these swaps on the BCs.
1. On BC2 there is a thick black wire that was in position 3 on my 93 but in position 2 on the 96 and 98s. This is the main ground for the heated window and a few other systems and MUST be swapped to meet. It’s an easy swap though.
2. On BC4 there is a Brown/Pink wire that was in position 8 my FXD. The LFT BC4s had a Pink/Black wire that performs the same function but it was in position 7. These must also be swapped to meet.

If you swapped the two wires listed above you should have MOST functions now: Brake & plate lights, wipers work correctly, hatch lock/unlocks with the doors, heated glass and LGOI on the VIC.
Here’s what you won’t have:
1. The window release button will only work with the ignition on. Per specs it should work when the Jeep is off as long as the system is unlocked.
2. The interior lights won’t come on when the hatch or glass is opened.

If you don’t care about those discrepancies, test the systems, install the interior trim and go get a beer. You’re done!

If you want everything to operate per Jeep specs read on. FYI - I don’t think it makes much difference whether this wiring work is done with the hatch on or off the vehicle.

PROVIDING FOR WINDOW RELEASE BUTTON AND INTERIOR LIGHTING OPERATION:
When adding these wires it may be easier to tape them together into their own harness and then tape and/or wire tie this harness onto the existing hatch harness. Best to get them routed properly and temporarily tape or tie wrap them together in a few spots before you tape it permanently so the harness is configured correctly.
An electrical tape tip: Give the tape a slight stretch as you apply it. As the roll of tape gets fairly small, start using a new roll and save the smaller roll. These are valuable if you ever have to make a wiring repair in a tight place.

WINDOW RELEASE BUTTON:
To get proper function of the window release button you need to provide a “hot at all times” feed to a wire in the hatch. I experimented with making the Pink/Black wire HAT by doing some creative temporary jumping at the fuse box. What that gives you is a window release button that works as it should but a wiper that doesn’t shut off when you turn off the ignition. It will only shut off with the wiper switch - don’t bother.





There is a white connector at the bottom center of the hatch with two wires = Pink/Black and Orange. The other side of the connector has two black wires that run about 6”to a square switch on the gate handle. Cut the Pink/Black wire a few inches back from the connector. (see pictures)
Another little wiring tip: When you don’t want a wire to ground out, cut it flush, lightly grip the insulation with the cutters and stretch is so the insulation is a bit longer than the wire inside it. You could also
Crimp it into an insulated butt connector. Either way, tape it off well, then fold it back and tape it against the harness inside the plastic sleeve as it will still be live when the ignition is on.

HAT wires are almost non-existent in the rear of the FX Jeep. I didn’t find any at the module in the corner by the spare tire and I didn’t want to run one from the fuse box. The best solution I came up with was to tap into the HAT red wire at the cargo light over the rear hatch.
This picture is the cargo lamp area with the lamp and body upper trim removed:


Now, there are two fairly easy connector options to get that powered wire through the BCs to HCR and into the hatch harness. See which of these wiring options best suits your need.
IMPORTANT: When you decide which method is best for you – Remember that the first step is to run the wire down through the right accordion rubber and into the body BEFORE you install the pin in the BC. (Getting the wire through that rubber isn’t easy) Once you have fed a generous amount down into the body you will have to reach in and fish it through the secondary reinforcement panel at the rear of the roof. Be sure to pull enough slack through to route it.
I tie wrapped it to the gray plastic wire run tube above the headliner, along the harness and down to the light. I used a Scotch-Lock type connector as it wasn’t a solder-friendly location. I don’t like to use scotch locks or connect a larger gauge wire to a smaller one but I couldn’t see any other way around it. It is well out of the weather and it only has to operate the window release button for a second at a time.

This picture shows a mockup of the two methods you can use:


Method 1:
If you were lucky enough to get some body harness wiring from the donor Jeep with the hatch, even a few inches with the connectors – Remove the pin retainer from the face of the donor BC4, lift the retainer clip and pull out the PNK/BLK wire and its pin. Remove the retainer from your ZJ’s BC4 and slip the PNK/BLK pin into the vacant position of BC4. Run the other end to the cargo light area and attach as described above.
On the wiring harness from your old hatch: Remove the pin and Pink/Black wire from the HCR and strip the PNK/BLK wire out of the harness – get a generous length, it has to follow the factory harness.
Now push the pin into HCR position 8 and run the wire along the harness and splice/join/solder it to the PNK/BLK wire you cut and left sticking out of the white connector.

Method 2:
The mockup picture 844 makes this easier to understand.
If you do not have any extra factory wiring you can do the same thing using generic male and female spade/blade type connectors and going through BC5 instead of BC4 but it takes a little care. Follow all the same instructions for the routing of the wires. Buy the terminals bare or strip the blue insulation off of one male and one female.
On your BC5 pull the pin retainer from the face of the connector, Crimp or solder the female connector onto the wire and feed it into the open position of BC5 with the “open” face of the connector facing away from the center spine of the connector. The female spade connector will actually lock into BC5 if you position it right.
The male spade connector doesn’t work quite as well in the HCR. The best option I see is to run the PNK/BLK wire from the hatch side right through the HCR and crimp the male spade connector onto the wire leaving it sticking out of the face of HCR with a few inches of slack. When it comes time to connect the wiring, first insert that free floating male into the face of the BC5 number 2 position.
Pull the wire back through from the rear of HCR while connecting BC5 to HCR as you normally would but take care that the back of the male pin falls into the slot correctly.
Method 1 is preferred but this will work. This should restore the window release button operation.

2. INTERIOR LIGHTING / VIC LGOI:
A quick explanation of the wires involved –
At the FXG BC6 there are two wires that matter. A TAN/BLK wire at position 9 controls the LGOI on the VIC and a GRY/BLK wire at position 5 controls interior lights when the LFT opens.
On the FXG both of these wires run to the HOLS on the latch. LFTs do not have the Gray/Black wire. They only use the Tan/Black wire which controls both of these functions through the BCM.

NOTE: If your ZJ does not have a VIC - or if you don’t care about the LGOI but you want the interior lights to work with the hatch - just swap positions of the GRY/BLK and TAN/BLK wires on BC6 so the GRY/BLK connects to the TAN/BLK wire in position 9 of HCR. Interior lights will work but there will be no LGOI. Again, you’re done!
FYI - You CAN jump or splice the GRY/BLK and the TAN/BLK together to operate off the existing hatch TAN/BLK wire but you end up with weird things like getting an LGOI when you open a door even though the hatch is still shut.
For proper function of the interior lighting with VIC LGOI read on.

The FXG has one HOLS on the latch mechanism. The LFT has the HOLS on the latch and a second HOLS on the glass latching mechanism. They are the same three place connector and switch on all years and on both systems so there is a place to add an additional wire for the lighting on the LFT HOLSs. The latch HOLS connector is way down in the bottom of the hatch. It’s a real pain in the neck to find and disconnect that connector the first time.



Next: Strip the GRY/BLK and TAN/BLK wires out of your old hatch wiring harness. Make sure the GRY/BLK has the pins at both ends and make sure the TAN/BLK has the pin for the HCR on it too.
Run the Gray/Black wire exactly where it originally went; from HCR position 5 down to the HOLS on the latch mechanism.
NOTE: You have to pull a small black plastic pin out of the rubber seal on the back of the connector to add the wires. The pin retainer from the old HOLS connector is made for three wires so use it on one of these connectors. On the other one the pin retainer might have to be notched a bit to accept the third wire.
Install the TAN/BLK wire into the Lift Glass HOLS and splice or solder the TAN/BLK and GRY/BLK wires together at some point along the harness.
FYI – The pins in BC6 fit the HOLS too.

WIPER MOTOR PROBLEMS:
The wiper motor on my 96 hatch was seized. This seems to be a fairly common ZJ problem. I rebuilt mine and then found this great writeup thread on the subject by gomes512.
http://www.jeepforum.com/forum/showthread.php?t=398760
This thread covers the subject quite well so I won’t duplicate it but I will add two things that were different on my rebuild:
The bearings are simple sleeve type friction bearings – no moving parts. The bearing at the trouble area was seized to the shaft on mine. To get it off I believe I actually knocked it further down the shaft with a tube because it was the easiest way to free it up, then cleaned up the shaft and worked the bearing off. Clean and reassemble per that link.
Also – During disassembly I found a circuit burned through on the circuit board of the wiper motor. I soldered a piece of buss wire across the terminals it ran between and it works fine now.

As mentioned before, the FXD wiper motor will install and work in the LFT but it will NOT stop or park like the LFT motor when the hatch or glass opens. If your LFT motor is junk you MIGHT be able to duplicate the LFT functions by substituting the PC board with connector from the LFT to the FXD wiper motor BUT I’m not sure if the spline type wiper motor arm will operate and park correctly over the LFT window. You’d also have to see if the contacts on the plastic drive gear are the same.

Let me know if this helped you and let me know if you found anything to be different on 94s, 95s and 97s.
 
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#4 ·
WOW Great Job. Im pretty sure some guys would like to do this. I would love to have the flip up glass on my 95.

Again great job lots of detail! [smilie=bal_cool.gif]
 
#5 ·
Thanks! I really appreciate it! I think the writeup took about 100 times longer than the swap!

I really tried to cover all the bases as far as what works and what doesn't work and I tried to write it for people that don't have much experience in this kind of thing so it ended up being quite long.
The problem with doing these writeups is that of course I know what I mean but does someone else know what I mean

Now I'm just waiting to hear from someone that actually uses it! I know someone was getting a later hatch for their 94 so I should hear from them soon.

Thing is - can you imagine how long the 5.9 5spd manual trans conversion writeup will be when I do that!?!?! [smilie=bal_ask.gif]

Thanks again folks - John
 
#6 ·
Bringing this one back from the dead.

I used this today to put a '98 lift glass hatch on my '93 ZJ. I had to stalk your photobucket account for the photos since they're not linking here anymore and I found most of them.

This was very helpful, the only thing that would have helped more would have been to know exactly what each wire was for and how it would test instead of just where they went.

I had to do this alone, so getting the old hatch off and the new on was a bit difficult. I ended up hoisting them up into a tree above the driveway with a tow strap and ratchet straps. I would've used a come along, but the tree branch was way too high and I would've had to be on a ladder to work it.
 
#7 ·
Back from the dead again....

I'm simply swapping a junk hatch door with a good one from a junk yard Jeep of the same year ('97). I had a heck of a time getting the good one off by myself and couldn't stand there and fiddle with the wiring too much so I just diked it off after pulling as much as I could out of the body. Just to clarify - there are connectors INSIDE the tailgate, correct? Or will I need to do some splicing? I haven't taken the junk tailgate off of my project jeep yet and just wanted to make sure (I moved and can't find my book right now).
 
#11 ·
Will do - I couldnt' do it with the one at the junkyard because it has that stupid latch problem. I crawled inside and yanked the upper panel off and found the mount bolts and got the door open that way, then had to balance the whole mess on my head while I fiddled with the hatch struts. :D
 
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