Tailgate replacement, harness swap

[rokr1292]

I got my hands on a tailgate from an 04 4runner, with spoiler, to replace the damaged and rusting one on my 08.

After doing a bunch of cleaning and polishing on the replacement, I went to attempt the swap today (a bold move with work tomorrow morning) only to run into a bunch of little issues.

The one that finally nixed my plans today was realizing the differences in the wiring harness between the two tailgates. the harness on the 08 connects to two things, the body harness and what appears to be a small ecu or sensor box. I found some speculation that the box was related to remote down functionality, but I cant help the suspicion that it's part of the RSCA system, or related to the additional airbags in the later models. The tailgate control module looks the same, so the harness that I need to swap only appears to go from that point above the headliner, and down to the rear door control module. unfortunately it also does branch off to connect to the rear brake light in the spoiler, so i will have to pop that off as well.

Does anyone here have any experience with removing this harness? I'll have to do it twice, so any tricks that anyone knows would be extremely helpful

TL;DR Please help me swap harnesses between an 04 tailgate (with spoiler) and an 08 tailgate (with spoiler)

 

[inscarguy]

My suggestion would be, if you unsure of the job take some pics if the installed harness and use that as a guide. There may or may not be a empty plug on your earlier harness for the 3rd lamp. If not swap all of the `08 stuff out and take the plug and wiring off the '08 harness for the 3rd lamp and work it in to your existing setup.

 

[iruninca]

I don’t know if it helps you at all in this situation, but I have an extra complete wiring harness/assembly from a ‘03 tailgate (w/ spoiler, w/o backup cam). So if you mess yours up or something, I’d be happy to send it to you.


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[Syr4RinNC]

I ran into the same problem recently. Actually there’s another thread a few down on installing a replacement tailgate and I have a few pictures of this situation.

When I replaced my tailgate on my 03 there was a single harness to swap out.

This time the donor car (an 05 )and mine (an 08 ) have two harnesses. I’m also not sure what that relay is and it’s confusing to me. The guy I bought it from unfortunately just saw through everything so I have to splice the wires back to the harness, but hopefully that’s minor

I guess question 1 is do both wiring harnesses plug in? I’m not really sure what that second harness goes into either.

2 would Be what happens/ what’s the downside if it does just plug in with mount power going to that.

Sorry you’re dealing with that - it’s frustrating for sure. Best of luck and let us know how it works out.

 

[rokr1292]

I don’t know if it helps you at all in this situation, but I have an extra complete wiring harness/assembly from a ‘03 tailgate (w/ spoiler, w/o backup cam). So if you mess yours up or something, I’d be happy to send it to you.


Sent from my iPhone using Tapatalk

If you dont mind me asking, how difficult was it to fish the harness out of the hatch? fitting everything up through the small passage next to the window looks like it might be the hardest part. Thanks for the offer but I think if I screwed up either harness, I'd still need a later model replacement

I ran into the same problem recently. Actually there’s another thread a few down on installing a replacement tailgate and I have a few pictures of this situation.

When I replaced my tailgate on my 03 there was a single harness to swap out.

This time the donor car (an 05 )and mine (an 08 ) have two harnesses. I’m also not sure what that relay is and it’s confusing to me. The guy I bought it from unfortunately just saw through everything so I have to splice the wires back to the harness, but hopefully that’s minor

I guess question 1 is do both wiring harnesses plug in? I’m not really sure what that second harness goes into either.

2 would Be what happens/ what’s the downside if it does just plug in with mount power going to that.

Sorry you’re dealing with that - it’s frustrating for sure. Best of luck and let us know how it works out.

I wasnt quite willing to trial the old harness in place. that one connector is the same, but pinned differently, and I didnt want to risk it being part of the RSC or SRS systems.

Was it much of a challenge getting the harness out of one hatch and into the other when you did your replacement?

 

[iruninca]

It wasn’t difficult to get the wiring OUT of the hatch, but it probably would be hard to put it back in. When I replaced my tailgate the new one already had the wiring harness, so I didn’t have to put it back in. I’ve fished wires through hatches before, and used a metal clothes hanger to pull the wires through.


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[Syr4RinNC]

Yea - the wiring harness isnt that bad. you just have to drop the head liner and get comfortable with it. Its pretty easy and when you drop the headliner theres plenty of room.

It was pretty easy for me to remove the harnesses from the donor. Sometimes theyre stuck pretty tight, but it came out really easily

 

[rokr1292]

Thanks for the replies folks,

if everything goes as planned, I'll be pulling the harness out of the replacement hatch today. I think I'm gonna tie a piece of twine to it before I remove it, so I have something to help me fish the 08 harness through later. It's a rainy day here, but if it goes fairly smoothly, I think I'm ready to tackle it the next time I get a sunny day.

 

[Syr4RinNC]

tailgate wiring diagram

So I had to splice all the wires in the liftgate/ tailgate to the wiring harness last night. In the event that there is a short or failure of one of these splices, does anyone have the wiring diagram for the tailgate/liftgate so I can figure out what wire is the issue if anything goes wrong?

 

[rokr1292]

So I had to splice all the wires in the liftgate/ tailgate to the wiring harness last night. In the event that there is a short or failure of one of these splices, does anyone have the wiring diagram for the tailgate/liftgate so I can figure out what wire is the issue if anything goes wrong?

What year is your truck/hatch? I have an intact harness (the one from under the headliner to the computer in the hatch) That you could have if you want it.

 

[rokr1292]

I finished my swap!

For my process, step one was to pull the harness out of the one I'm installing. pulled it out pretty easily, but with a lot of wiggling, with a wire coathanger hooked around the last blue plug. The spoiler needs to be removed to get it out.

Remove the spoiler on the broken hatch, pull the harness out of the door (did not need to disconnect from under the headliner for this part) Disconnect sprayer nozzle (i used a pair of surgical clamps to keep the cleaner from running out).

Have a friend support the hatch while you disconnect the struts and undo the 4 nuts holding the hinges onto the rest of the car. Do the reverse for mounting the new hatch. use the coathanger to pull the harness through the new hatch and reassemble.

I transplanted the body match handle cover, newish button, newish license plate lights, and lock cylinder. I havent decided what spoiler I prefer so I'm holding on to both at the moment.

In trying to find a way to reassure myself that this would work as expected, I saw that the door controller is the same part number, so everything after the door controller seems the same year-to-year. the wiring that goes to the mystery box under the headliner seems to lead back into the body harness instead of to the door controller, for anyone interested.