Hatch Problems

[J_MaC]

First off, hello. I'm fairly new I guess, do a lot of reading and not much posting. The site is great.

Anyway, onto my problem. 2007 t4r v6 sr5 4x4. I'm having a strange hatch issue, It is constantly losing it's rear window normalization memory and the door won't open at all unless the vehicle is running. When I put the key into the back and turn it nothing happens at all. When I press the hatch open button on the back without the vehicle running nothing happens at all, no sound of the motor trying to unlock it or anything. When I press the window down button on the remote all I get is a solid beep and nothing happens.

I was leaning towards it being a low voltage issue from the battery because it works fine when running and it still had the original battery installed in it. So I changed the battery and nothing changed, still acts the same.

I can get into the vehicle, turn the ignition on without starting it, normalize the rear window and get it working properly, so that the wiper and pump work, but it still will not open unless I start it. Once I start it, it will also not open until I hit the unlock button even though all the doors are still unlocked.

It just seems strange that this gradually came on and more functions have quit working correctly. It started with the wiper and pump not working, a quick read through the manual revealed that they won't work unless the window is all the way up. Quick down and up and problem was solved, so I thought. Now it has progressed to this.

I'm kinda leaning toward the rear hatch ecu being fried. I haven't opened up the panel yet to have a look, but I will this weekend. Hopefully it's just a few wires, but the erratic operation make me think otherwise.

Any help would be greatly appreciated.
Thanks for you time.

 

[BlackWorksInc]

I would visually inspect the Rear Door ECU and see if it is corroded/damaged in any way. If not I would check power & ground for the ECU and make sure they are clean; it wouldn't hurt to see if you can also see varying voltage on the communication bus when you hit switches just to see if it is receiving/outputting commands correctly.

 

[J_MaC]

Will do. Thanks.

Any recommendations for a good place to buy the ecu if it's fried and I can't find one at the wreckers?

 

[BlackWorksInc]

COMPUTER, MULTIPLEX NETWORK DOOR for 2007 TOYOTA 4Runner. #8922235010

That's it I think?

 

[J_MaC]

Wow, that's spendy for a little module. Hopefully I can find one at the yard if it's fried. On the plus side, I found a thread with my exact same problem. Couldn't find through searching on here, found it through duckduckgo...

http://www.toyota-4runner.org/problems-warranty-issues/2007-03-4runner-back-door-problems.html

Hopefully mine is just the same issue as these two.

 

[J_MaC]

Looked through the harness a bit, haven't found any broken wires or any corrosion on the plugs. Tried a different rear door ecu and it acts the same.

So what this is actually doing is cutting the power to the rear hatch completely when the ignition is turned off. Once turned on, I have to go through the motions to get everything working again as if I had just disconnected the battery. I can't find any fuse pertaining to constant power to the rear hatch. Is there a relay or something like that that controls it?

 

[J_MaC]

So I'm assuming that this is the power plug for the ecu.

I have constant power from the thick blue during all key positions. I get a good ground through the thicker white wire. When the key is turned on, I get constant power through the small brown wire also.

What are the red and blue/red wires for? Communication from the other ecu? because they are supplying nothing at all.

I also dug through this loom thinking that maybe a wire got pinched by some ice or something. But all is fine in there too...

 

[J_MaC]

Ok. How does this thing remember that the tailgate is closed once the ignition is shut off? Is that in the latching mechanism? I can't find any broken wires anywhere.

 

[J_MaC]

Solved!!

So apparently I'm forging new ground with this eh?

Anyway, Ive found the problem!! After about 12 hours of screwing around with it yesterday, I came upon some information in the wiring diagrams that I have here. Solid blue and blue/red are supposed to have power at all times to the ecu power plug. I had 12 volts to the blue but nothing to the blue/red. Blue/red had power up top in the loom from the body to the door, but nothing down below. I taped a wire to the harness and pulled it up out of the door and started to probe the wire in several spots. I found a piece where it had power and 8 inches away had nothing. Strange thing is that the wire appeared to have nothing wrong with it at all. I cut out that section of wire and soldered in a new piece with heat shrink. Once I had the old section out, I grabbed it at both ends and pulled. Sure as shit, it was broken inside the insulation with no signs that there was anything even wrong on the outside. Not a mark, nothing.

So, after about 18 or so hours of investigation and repair time, including last weekend, My wife now has a fully functioning door again. That otta be good for a bj.....

Cheers

 

[awdjunkies]

^ wow!!!

 

[John619]

I'm currently experiencing the same issue. Just installed a new multiplex ecu and nothing. I bet my issue is the same wire. Do you have a picture of what part of the harness lost continuity?

 

[Tyota89]

Nice find man..reason I hate wiring. Mulitmeter is your best bet [MENTION=23200]John619[/MENTION] your issue may be different from his. Especially if it is electrical.

 

[J_MaC]

I'm currently experiencing the same issue. Just installed a new multiplex ecu and nothing. I bet my issue is the same wire. Do you have a picture of what part of the harness lost continuity?

Sorry I didn't see your reply. I'm not getting notifications whenever there's a reply on my threads for some reason...

Anyway. That picture of the plug further up is the one that feeds power into the back door ecu. Like I said previously, 2 of the wires going into that plug are supposed to have power at all times. Ignition on or off, doesn't matter. If you find one doesn't have power, just keep probing it until you find a spot on it that does. That's how I found it. It was a pain in the ass...

 

[JrAdrock80]

OMG! I am in such amazement that I can barely think straight.

Today J_MaC you are my freaking hero......... Not kidding! I have been searching and searching because I had the EXACT same issues you were having. I had to turn the key to On and then hit unlock to open the tailgate. As soon as the you turn the ignition off..... Tailgate would not open. To use the defrost or wiper, I had to have the car running and I would have to bump the rear window down an inch or so and then close it and everything worked fine. As soon as I turned off the ignition, it wouldnt work until I did the same procedure again. If the ignition was on, you could program the auto up and down on the window etc.

I pulled my hair out for almost two years over this. I tried every normalizing procedure I could find. I took the panel off and tried all the connections. NOTHING and I mean nothing worked...... It all started when I replaced the battery. The battery was dead and it was getting worse. After replacing the battery the rear hatch just stopped working like everyone experiences, but I couldn't get mine reprogrammed. I talked to some mechanics and they went on and on about microswitches and replacing the ecu and wanted big bucks to do it. I'm a car guy and have done my fair share of mechanics so I have a hard time paying people for things I know I can do.

So today I thought I would take a crack at it again. Like before I was getting nowhere. I thought I would search one last time. Your post popped up on my Google Search and you described the exact same issue I had. I pulled out the old multimeter and low and behold the blue and red was at 0 volts. I pulled the rubber harness cover at the top of the hatch and was getting 12 volts. I ended up tracing the wire just inside of the hatch and noticed the electrical tape was all jacked up...... Wire was crushed! Ran a patch wire and soldered it in. 12 volts to the blue and red at the plug!!!!!!!! Threw the whole thing back together and voila, everything works!

I am so damn happy right now I can hardly contain myself. You are the freaking man! Thank you, thank you, thank you, thank you, thank you for sharing this. You saved me hundreds of dollars for such an easy fix.

Now, this can't be a coincidence. I think there is a small design flaw in the way the wire is ran. Mine was crushed and corroded, which appears to have made it oxidize and deteriorate inside the shield. Eventually it separated and lost connection. I will gladly share this whenever I see someone with a similar issue.

Good job brother! Have a nice cold one, you deserve it!

 

[J_MaC]

Glad I was able to help.
I no longer own the 4runner. But I hope that this is a lasting contribution that'll continue to help others in the future.

Cheers boys

 

[sbenner44]

Still no luck.

Glad I was able to help.
I no longer own the 4runner. But I hope that this is a lasting contribution that'll continue to help others in the future.

Cheers boys

Boys I’ve tried everything, new motor, new ecu, checked all the wires...nothing it will work once when I reset the rear window then it looses it’s reset. I can’t do it from my key hole on the tailgate as my key doesn’t fit it...
my battery is a bit low around 11.5 but when the car is running the power at the ecu plug was over 14v. Can anyone help!?

 

[sbenner44]

Boys I’ve tried everything, new motor, new ecu, checked all the wires...nothing it will work once when I reset the rear window then it looses it’s reset. I can’t do it from my key hole on the tailgate as my key doesn’t fit it...
my battery is a bit low around 11.5 but when the car is running the power at the ecu plug was over 14v. Can anyone help!?

It closes for a second and does some weird half open.

 

[KenBrunner]

Helped another one J_MaC

The gift that keeps on giving... 7 years later we fixed another one!

That blue/red wire is a weak link. Many of the other wires are a heavier gauge. It's a design flaw. I'm sure the amp requirement is low, but the tiny wire cannot stand the sustained abuse in this environment. I didn't do any voltage testing, just continuity. I popped the bundle hatch cover to access one end of the wire and had no continuity in the connector at the ECU. Never found the problem area. I just pulled a new wire and spliced at the body access and threaded the new wire all the way down the hatch to behind the ECU (removing the 5 screws) and spliced in there.

Grateful for this forum and contributors like J_MaC and JrAdrock80.