I just got a 1999 4Runner SR5 and I love it, but it has a few quirks that need to be worked out, the first being the rear window/wiper/defroster not working. I've searched a bunch and have seen many similar threads, but none with the info I need to solve the problem. Please help!

I can lower the window using the key in the tailgate and I've already checked that the window lock button is not engaged.

I found this schematic on one thread and it's been helpful, but also a little confusing:
http://tacoma.site40.net/4Runner_96-...i/043pwrww.pdf

I was able to check that the window limit switch is working, creating a short when the window is closed and an open when it's open. I measured this both at the switch and at the Back Door ECU so the wires are OK.

What is bothering me is that the schematic talks about the Back Door ECU having 26 terminals, when mine only has 18?? I also get different behavior than what the 'Service Hints' say to check. ie, I don't get 12 V between Pin 1 and Ground, it's continuous. However I do measure a little more than 12 V at Pins 10,11,12,&13 relative to ground (picking this up at the gang of B/W wires). Also when I unplug the 18 Pin cable going into the ECU, I only get the 12 V at Pin 12.

Any electrical people out there know what my problem is??

Thanks!

OK, where do we start. I'm not sure the schematic says it has 26 wires, there are 26 possible terminals on a 2002, but you have a 99, so there could be differences. Still the system overall won't be too far off. I don't follow what you mean when you say you don't get 12V between Terminal 1 and ground, it's continuous. And what do you mean by "relative to ground"?

Lets start with the color of Terminal 12, is it yellow or blue? I think @TheDurk may have access to some earlier schematics. Let's hope so for simplicity. Bottom line the fact you seem to have failures all around makes me think the problem will be simple in nature, not necessarily easy to find. You may not have 12V where you should, or either the Body ECU or Back Door ECU have failed. We can solve this though, nothing is beyond a few simple tests.

Please start by checking the 30A power fuse, the 10A ECU-Ign fuse, and the 15 accy fuse, use a test light or multimeter. Do not rely on a visual check.

We'll be here

is the "little more than 12V" while the vehicle is running? also I think a normal for a car battery not charging is 12.3 and 14.1 when charging i.e. vehicle is running. My cousin fixed a dent I had in the back hatch a year ago and had the problem where the window wouldn't roll down and it turned out he forgot to plug one thing in when reassembling.

Ive heard before that they changed the door wiring between a certain range of years. (possibly on blktpsgtr's build I don't remember, but he did tear into his new and old hatch and there is pictures if you want to check it out and find it in his build thread.) basically, check EVERYTHING related to the problem thoroughly and report any findings on here.

also Im a little confused, the window rolls up and down with the key only and thats it? if thats the case Id wager that the wiper and defroster not working is because of the switch and its not seeing that the window is all they way up, canceling those two features

I just compared my paper '99 4Runner EWS and the on-line 2002 EWD and they are identical in all respects, including the service hints. T12 on the Back-door ECU is GREEN in both, by the way. {I'm guessing IBall fat-fingered T1 in his post.] The B18 plug for the Backdoor ECU should 26 pins (2 rows of 13) although several (five) do not have wires.

If you don't have 12V+ at Pin 1 on the plug but rather ground continuity something is effed up that we have to get right from the getgo. Try Pin 1, with it unplugged from the Backdoor ECU, which is a corner pin with a solid blue wire. Measure to a good chassis ground or even battery negative. If no 12V+, verify the 30A POWER fuse with a test light (ignition on). That blue wire comes straight from the fuse and HAS to have 12V+. If it doesn't we start tracing it back to the fuse panel before anything else.

See plug B18 on Page K of attached for pin-out (all 26) of BackDoor ECU, hereafter BD-ECU as I am tired of typing it out.

Attached Images

connecto.pdf (254.1 KB, 332 views)

Actually, I didn't fat finger T12. I was wondering if he had a different connector configuration since he said he had 12V at T12. I was hoping by identifying the color we could see which input it should be. But if you say the diagram is the same, T12 is the window motor. I hear you on the BDECU, I don't even want to Hyphenate.

Gotchya. I apologize to your finger.

Thanks for the quick response guys!

So I realized I had my terminal numbers wrong. I thought the # on the diagram would corresponded to the Pin # on the connector, but that's not always the case, so now I'm going by wire color. (Though that doesn't completely match either.)

For example when I said I had 12V at T12, this is actually T1. It's a blue wire, heavier gauge, but it's not in the corner position of the connector. But it's the only place I get power when the IGN is off.

Going through the Service Hints using this new approach (going by color, not #) I also confirmed that:
-I get 12 V at T3 when the Ignition is on
-There is continuity (a short, 0 V) between T26 and ground.
-T9 & T10 both get grounded when using the tailgate switch Up and Down, respectively.
-I DO NOT get the 12 V at T11 when pressing the Up switch.

I didn't test the down switch (T12) because I'm doing this solo and had to use duct tape to keep the UP button pressed on the dash while using the meter in the back...


What's bothering me now is that my connector doesn't look like anything on the .pdf (pic attached) so now I'm wondering if the whole BDECU was swapped out with something different?

@sportrunner2001 can you post a link to blktpsgtr's build? I tried searching 'blktpsgtr' but only found this thread. Thanks for your patience with the FNG!


Also, I checked the fuses with a DMM and they're all good, and I double checked that the window limit switch is operating correctly.

Attached Images

 

The only explanation I can think of is a PO swapped in a different liftgate (or, less likely, a BDECU, from '96-'98. I know they are different, but I don't have the diagrams.

Can you get a part number off the BDECU?

Also, check the harness between the liftgate and the body. The wires tend to break and short where they flex. Since window works with key, we may have a communication breakdown at that harness.

@Schnaars here it is: Blcktpgsr's '97 transformation

My bad i spelled his username wrong. Be warned, theres 55 pages of building in there and no table of contents but its worth reading through all his great work. I have the link in one of my bookmark folders because I like to get inspiration haha. Somewhere in it he gets a hatch from a JDM Surf and swaps in onto his Runner.

I also remember another thread about someone getting the wrong year of hatch from a junkyard and the wiring was wrong. Ill post up a link to that on this post if i find it.

I have all the patience in the world for someone who tries to find out the problem, then asks! instead them asking something vague or "how much lift do I need to fit 33s and what lift should I get?"

*EDIT: Here's the link. Not a whole lot of info on the changes in wiring between years but @DeathCougar talks about some of them in that thread, Maybe he can chime in on what your dealing with and help.

Link: Auto industry full of thieves

It could also just be connection problems, explore that first since might be easier. Or search the different ranges of year's wiring diagrams and find out what matches what you have, hopefully the same year as what your vehicle is...

*double edit: MY 100TH POST WOOHOO!

3rd gens used 3 different rear gate computers.

I don't know the part numbers, but the colors were as follows:

96-98 Blue
99-00 Orange
01-02 Red

If yours is different from what's listed above, someone may have messed with the system. The Blue and Orange will physically not interhange, meaning you can't use a 99-00 ECU in a 96-98 gate. Not 100% sure about the Red and Orange interchange though.

The Part info for my BDECU is :MFR: Denso, PN :85930-35020 (I think, check out the pic)

So I think we've narrowed it down to either a liftgate that's not 99-00, or a broken connection between the body and liftgate. I guess I'm hoping for a broken connection since I don't know what I would do with the alternative...

I get ~11 V at Pins 1&2 where the Up/Down SW on the dash plugs in, so I'll see if I can trace that back to the Body ECU. It looks like I can find this behind the kick panel next to the steering wheel? I haven't uncovered this yet so wish me luck...

Also, the schematic says the Up switch sends a signal (i'm guessing the 11V) to T5 on the Body ECU to T7 on the Body ECU to T18 on the BDECU.

I tried checking T18, but it's a little weird. It says T18 should be violet and white, but I don't have that color going directly into the BDECU. However I do have a V/W wire going into a dark gray harness which connects it to a light green wire which DOES go into the BDECU. I'm guessing this is T18?

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There ya go! Wrong tailgate/ECU/Wiring harness.

That ECU is the 96-98, and won't work with your 99-00 system.

Here is what should be in there:

1998 99 00 Toyota 4Runner Window Relay Computer 85930 35060 | eBay

The wiring on the gate shouldn't even plug in, so sounds like someone swapped the gates, or the wiring harness.

Thanks DeathCougar!

I'm glad we finally got to the bottom of this, though I'm a little worried that this means it was in an accident or something...

Also it sounds like if I want the wiper/window/defroster to work properly, I'll have to buy the correct ECU and then undo their retrofit and re-route all the wires into the correct connector. And I just thought it was a bad switch...


Thanks for all the responses! This is forum is an amazing resource.

To nail this down, plug your VIN in here to see if it could possibly belong to your model.

85930-35020 - Toyota Parts Zone

Assuming it doesn't, I have to figure these things never worked since the new liftgate got swapped in. They probably just shipped in 12V+ on the blue wire, allowing key operation of the window and left it at that. Do you have keyless entry? I doubt that works either. Does the rear door lock with the rest when you use the key? I'm trying to figure how extensive a transplant job they did.

Another thing, on my '99 SR5, the factory liftgate is one of the parts that had a VIN number sticker applied to it. On mine, it is on the side surface that points toward the left taillight, and can only be seen with the gate open. It's sort of in behind the 4 in 4Runner. I think that started in '99, so an earlier liftgate might have no label at all.

The other thing to look for is the VIN tag on the gate. Tag is on the side of the gate. If the tag is missing or wrong, you have your definitive proof. Only exception is if your truck was imported through Canada (will have maple leaf on sticker on door jamb)