2008 Tacoma Master Window Switch not working.

Searched through the threads here to try and find an answer, but couldn't find the fix.

Went out to my truck this morning and the driver's side window controller wouldn't work for any of the windows. The lock/unlock mechanism still works though and all the window controllers on the specific doors work. Checked to make sure the window lock wasn't on, replaced fused, red wire running to window switch has voltage and the LED on the window controller circuit board lights up.

I'm out of ideas, anyone have any suggestions?

 

Had the same problem on the 4Runner in my sig. Ended up getting a nice condition used one on Ebay and it fixed it. Not sure if that's what you need, but if you do, check out parts on Ebay. My seller had a 30 day return policy with a small restocking fee so felt it was safe to try.

 

Since the LED lights, that proves that there is power to the master switches. All of the other window switches use the ground at the master switch to complete their circuit to ground, so that proves that the ground for the master switch is good. There is only 1 relay in the system and that is the power supply for all the switches. There is no computer control for the individual windows. Logic would indicate that the problem must be the master switch assembly. Here's the schematic for the power windows.

http://www.customtacos.com/tech.old...toyewd/06toypdf/ewd/2006/tacoma/h/em01d25.pdf

 

Just replaced the entire master switch and still nothing. The lock button still works, but none of the window buttons work. Any other ideas?

 

That doesn't make sense. Since the individual switches make the 3 windows go up and down, we know the motors are good, and the individual switches are good and the wiring all the way to the master switch is good and the path through the master switch to ground is good. Since the LED on the drivers switch is lit, we know there's power to the master switch. There's nothing else left.

Forget about the door locks. They're completely separate circuits from the windows.

 

I agree, it doesn't make any sense to me either.
When I press the window switches on the master there is no noise at all.

 

Have you ohmed out the master window lock switch to make sure you get a short when in normal mode and an open circuit when in lock mode?

 

Power window switches are a lot more complex than a simple on/off switch. When your finger is not touching the switch, both motor wires are connected to ground. When you push or pull the switch, it connects 1 wire or the other to +12v. Then you have another switch on the other end that works in a similar manor.

 

The master lock switch controls if the motor has a path to ground/negative.

 

Oops. I thought you were refering to the actual master window switches. The lockout switch has to be working because the 3 windows work from their respective door switches.

 

I didn't have time to ohm the switch last night, but on my way to work today confirmed that when engaged the separate window door switches won't put the windows down and when unlocked they work as intended from each separate door.

 

I’m not sure why the driver door courtesy light switch appears on the wiring diagram. Have you confirmed that is working? I can’t see how that would be part of the power window circuit but it’s on the wiring diagram so might as well rule it out. If you press that switch you should see the door open dash light turn off and vice versa.
From what you tested the master lock switch is doing what it should.
After you rule out the driver door courtesy switch see if the behavior of the master switch panel changes when the door is open compared to when it is closed. Jiggle the rubber boot between the driver door and cab while you are toggling those master panel window switches.
I agree that you guys have tested out all the obvious stuff so that’s why I’m suggesting outside the box experiments.
My gut feel is that there is a bad ground connection but at the same time studying the wiring diagram doesn’t indicate a potential location based on your test results.

 

The courtesy light switches only go to the ECU and the only thing the ECU has to do with the circuit is to turn on the P/W relay which supplies power to all the window switches. So, since the windows work from other switches, that can't enter the picture. I have studied the schematic and reread the symptoms multiple times and there's only 2 posibilities that I can come up with.
1. The replacement master switch has the same failure as the original. (Highly unlikely)
2. The master window switch power wire is broken at the door hinge with only 1 strand left. (Enough to light the led but not enough current capability to run a motor). If this is the case, the voltage at the switch should drop when the switch is activated. This also seems like a highly unlikely possibility for the failure.

 

I have some more time tonight and it's finally not raining here so I'll take a closer look at option 2 since option 1 seems even more unlikely to me.

Does that wire boot at the hinge just pull out from either side so I can slide it over and check for any issues with the wire?

 

The best way to check for option 2 would be with a volt meter while activating the switch. However, the 1 strand theory seems almost as unlikely as option 1. I've never had the rubber boot out on a Taco, but I would imagine it just pops out.

 

I agree the possibility of two master switch assemblies having the exact same issue are highly unlikely.
If the ground connection is hanging on by a thread I would expect that it would have become a fuse and burned open when the window motor was enabled.
I’m curious what you find when you investigate the wiring behind the rubber boot. Don’t just look at the insulation and assume if it’s okay that the wiring it protects is also not broken. You may have to pierce the insulation with your measuring probe to get the reading.

 

Pulled the rubber boot off from the door side and pushed it as far towards the cab that I could and didn't see any issues with the insulation. Was trying to figure out how to pull it off from the cabin side when I checked the master switch and everything was working all of a sudden.

I'm taking that to mean there probably is a wire issue and it's either inside the insulation or happening somewhere else along the wire.

 

I have seen the wire break inside the insulation with nothing visibly wrong with the insulation. Is it possible that you had voltage and lit LED with the door open, but only checked for window operation with the door closed? A broken wire can make contact at some point in the door opening range and no connection elsewhere.

 

Good to hear that the failure point has been identified. Now the fun part of figuring out which wires are broken.

 

Oh boy, those are the fun ones to troubleshoot. The cabin side of the boot comes off the same way as the door side except I don't think it's got the extra long flap of rubber. FWIW, it's pretty easy to remove the panels on the door and at the kick plate to get access to the ends of the wire, there's a good set of instructions in the heated mirror kit thread. You'll need a small flat head screwdriver and a #2 Phillips:

https://www.tacomaworld.com/threads...update-thread-pic-heavy.377840/#post-10363565

(I linked to the post just below the file attachments that have the instructions so that you wouldn't have to scroll through the entire first post to get to them, the door instructions are the same in all of the attachments, just pick whichever sounds best)