Toyota Highlander rear window roll down

My 2007 Highlander drivers side rear window rolls down by itself during the night. It has done this two different times and seems to always do it when it is raining.

The second time it happened, it would not roll back up. I had to remove the door panel and hot wire it direclty with power to get it to roll up. Then I started trying to trouble shoot the problem.

The plug running to the window motor has two wires that are supposed to be powered only when the switch is pushed, and when pushed, the ground and power wire alternates depending on the direction the switch is pushed. However, one of the wires is hot all the time, regardless if the switch is pushed or not. I suspected that the master control switch may be the cause because at first, it was acting up at the same time, i.e., it would not work to control the other windows in the vehicle but only the drivers window. Having said that, it now is working for all the windows except the problem window (drivers side rear window as described).

One thing that still makes me doubt that the master control switch is the sole problem, is because when I remove the master control switch by unplugging it, the problem window in the passenger door still does not work and the plug going to the motor still has constant power on the one wire and ground on the other (which consequently rolls the window down), and movement in the switch for that door has no affect.

Does anyone have any experience with this? Could the master control switch be the sole problem? Or is there another potential cause such as a relay located elsewhere causing the problem? I would like to 100% isolate the problem because a new master switch is pretty expensive and I hate to purchase one only to find out that it is something else. Any help or advice would be greatly appreciated. This is has been extremely frustrating.

thanks

Are you able to turn off the child control and make it stop?
Also when it starts rolling down can you stop it by using the driver switch in the up position?

Are you able to turn off the child control and make it stop?
Also when it starts rolling down can you stop it by using the driver switch in the up position?

I have not tried to turn on the child control to see if that stops it from happening. The two times it has done it has been in the middle of the night. We just wake up to see that it has rolled itself down sometime during the night. It is really odd. Pretty worrisome too knowing that it just does it all by itself. We can't trust it to lock stuff up in the vehicle because we never know when the window will just roll down.

Since there is still power on one of the two wires running to the defective window, even if the master control switch is unplugged, I am thinking that there might be another relay somewhere that is not working properly. Does anyone know if there is another relay in the dash of the vehicle? I am totally stumped with this.

I was hoping that when I pulled the master control switch, the power would then be cut from the hot plug going to the defective window which would confirm the thought that the master control switch is bad and needs replacing. However, since the power is still present even when the master control switch is unplugged, I am not so sure that's my problem.:headbang::dunno:

Yikes I didn't know it was happening with the KEY off!!!
Any modifications to the vehicle? Stereo, amps, aftermarket GPS, anything like that.
Do all your windows still work with the key removed?

Sounds like something has been mis-wired or is shorting out giving it power all the time?

Yikes I didn't know it was happening with the KEY off!!!
Any modifications to the vehicle? Stereo, amps, aftermarket GPS, anything like that.
Do all your windows still work with the key removed?

Sounds like something has been mis-wired or is shorting out giving it power all the time?

Thanks for your reply funman1. I think I am getting closer to resolving the issue. I noticed that the kick panel area was wet so I pulled off the drivers side kick panel to inspect it closer. There is several electrical connector plugs behind the kick panel that were dripping wet with water. I dried them out with a hair dryer and found one of the plugs was a bit corroded. I cleaned it up with electrical contact cleaner and reinsalled everything. Everything now works as it should. I think the water was shorting the plugs out and the corrosian was effecting the rear window.

I did find that the drain in the sun roof on the drivers side was blocked at the entrance of the drain hole. I cleaned it out and tested it with a water hose to make sure it was draining properly and also checked to make sure no more water was coming into the vehicle. I did not see any sign of water coming in so hopefully that solved the issue. I also drenched the windshield and wiper area just to make sure the water wasn't coming in from that area. So far so good. Guess time will tell when the next rain storm comes along.

I still find it hard to believe that the clogged drain hole in the sun roof could cause it to leak into the vehicle in the kick panel area. Does anyone have any idea how that can happen?

Thanks for your reply funman1. I think I am getting closer to resolving the issue. I noticed that the kick panel area was wet so I pulled off the drivers side kick panel to inspect it closer. There is several electrical connector plugs behind the kick panel that were dripping wet with water. I dried them out with a hair dryer and found one of the plugs was a bit corroded. I cleaned it up with electrical contact cleaner and reinsalled everything. Everything now works as it should. I think the water was shorting the plugs out and the corrosian was effecting the rear window.

I did find that the drain in the sun roof on the drivers side was blocked at the entrance of the drain hole. I cleaned it out and tested it with a water hose to make sure it was draining properly and also checked to make sure no more water was coming into the vehicle. I did not see any sign of water coming in so hopefully that solved the issue. I also drenched the windshield and wiper area just to make sure the water wasn't coming in from that area. So far so good. Guess time will tell when the next rain storm comes along.

I still find it hard to believe that the clogged drain hole in the sun roof could cause it to leak into the vehicle in the kick panel area. Does anyone have any idea how that can happen?

WHAT! This is my exact problem. I've had the rear driver's side motor warrantied 3 times now. Always blows during a rain storm and I find the window down the next morning and the interior soaked. I'm traveling now but will report back my findings around a corroded connection. If this works you will have solved a years long mystery and hundreds of hours of worry and headache.

Thanks for your reply funman1. I think I am getting closer to resolving the issue. I noticed that the kick panel area was wet so I pulled off the drivers side kick panel to inspect it closer. There is several electrical connector plugs behind the kick panel that were dripping wet with water. I dried them out with a hair dryer and found one of the plugs was a bit corroded. I cleaned it up with electrical contact cleaner and reinsalled everything. Everything now works as it should. I think the water was shorting the plugs out and the corrosian was effecting the rear window.

@Triton1 did this end up being the fix? Or did the problem recur?

@SteveAstin we’re you able to fix your rear window using Triton1’s discovery?

I have a 2005 Highlander and when it gets wet outside, often the rear window will go down on it own and I can not get it to go back up.

What was your solution?

Thanks for your reply funman1. I think I am getting closer to resolving the issue. I noticed that the kick panel area was wet so I pulled off the drivers side kick panel to inspect it closer. There is several electrical connector plugs behind the kick panel that were dripping wet with water. I dried them out with a hair dryer and found one of the plugs was a bit corroded. I cleaned it up with electrical contact cleaner and reinsalled everything. Everything now works as it should. I think the water was shorting the plugs out and the corrosian was effecting the rear window.

I did find that the drain in the sun roof on the drivers side was blocked at the entrance of the drain hole. I cleaned it out and tested it with a water hose to make sure it was draining properly and also checked to make sure no more water was coming into the vehicle. I did not see any sign of water coming in so hopefully that solved the issue. I also drenched the windshield and wiper area just to make sure the water wasn't coming in from that area. So far so good. Guess time will tell when the next rain storm comes along.

I still find it hard to believe that the clogged drain hole in the sun roof could cause it to leak into the vehicle in the kick panel area. Does anyone have any idea how that can happen?

Was gonna say....Water! Had a late 90's GTI. They were prone to rusting out on the bottom of the windshield. Water would drip down onto the fuse panel and close the circuit on some of the relays. Horn would go off randomly as well as the buzzer that goes when you leave your key in the on position with the door open. Was maddening for a bit til if figured it out!

Thanks for your reply funman1. I think I am getting closer to resolving the issue. I noticed that the kick panel area was wet so I pulled off the drivers side kick panel to inspect it closer. There is several electrical connector plugs behind the kick panel that were dripping wet with water. I dried them out with a hair dryer and found one of the plugs was a bit corroded. I cleaned it up with electrical contact cleaner and reinsalled everything. Everything now works as it should. I think the water was shorting the plugs out and the corrosian was effecting the rear window.

I did find that the drain in the sun roof on the drivers side was blocked at the entrance of the drain hole. I cleaned it out and tested it with a water hose to make sure it was draining properly and also checked to make sure no more water was coming into the vehicle. I did not see any sign of water coming in so hopefully that solved the issue. I also drenched the windshield and wiper area just to make sure the water wasn't coming in from that area. So far so good. Guess time will tell when the next rain storm comes along.

I still find it hard to believe that the clogged drain hole in the sun roof could cause it to leak into the vehicle in the kick panel area. Does anyone have any idea how that can happen?

Genius!! that's exactly what was happening with my 05 Highlander Hybrid, woke up one morning and saw the window down after a rainy night, when I turned the key the rear wiper started going off on its own. Unclogged sunroof drain and after cleaning and drying the connectors with some alcohol that did the trick, you saved us a fortune in mechanic bills thanks!

Here is what I found out. The water drain holes from the sunroof get plugged up with leaves and stuff. The water has nowhere to go but under the dash where it reeks havoc on the electrical system and caused my windows to roll down. I cleaned out the drain holes, dried out the car and it never happened again.