This is driving me crazy!

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Sep 22, 2011 | 05:04 PM

DBLTRGR

Thread Starter

Racer

Joined: Apr 2011

Posts: 254

Likes: 0

From: Great Falls MT

This is driving me crazy!

The passenger window goes down all by itself. I've checked switches on both doors for corroded terminals, taken apart the control modules in both doors to check the circuit boards for any cracked solder joints, checked the door wires running thru the rubber accordions for bare wires and cleaned those connections. What else? Could the up/down micro switches do that? The ones that regulate where the window stops at? I've also had the window refuse to go down from any position using either door switch.

Sep 22, 2011 | 08:40 PM

TEXHAWK0

Le Mans Master

Joined: Sep 2003

Posts: 8,847

Likes: 795

From: Longview Texas

First, there are no micro-switches to stop the window. It simply drives the window up against the stops until the motor stalls.
The window regulators are notorious for working one time, and the next time you try to operate the window, it does not work.

I have never seen a post where the window operates by itself.

I would check the switches to make sure that they are not shorting out internally.
Sounds like your problem is not one of a bad connection (corroded terminals) but rather one where the window is getting power when it should not.

Last edited by TEXHAWK0; Sep 22, 2011 at 08:43 PM.

Sep 22, 2011 | 11:20 PM

toddk

Racer

Joined: Feb 2004

Posts: 359

Likes: 7

From: St. Paul MN

Quote:

I've also had the window refuse to go down from any position using either door switch.

Sounds like you've searched and visited all the common suspects. Please provide a little more detail about your issue.

Did this problem start after any recent work or repairs? Is there a particular time that it goes down, like when using your key fob? When you open/close a particular door? Any action you can do to trigger it? Does it ever go UP by itself? Driver's window is responding 100% as expected?

Quote:

checked the door wires running thru the rubber accordions for bare wires and cleaned those connections

Did you inspect the door switch-to-DCM cables? A short there (in either door) would also act like a button press.

Either of the window control switches (driver's passenger remote control, or passenger's local control) could cause the passenger window to open & close by itself if one of them has an intermittent short as TEXHAWK0 said. To try and narrow it down to one, tap/whack around each of the window controls to try and cause an unexpected window movement.

Also check your OBD port for a window valet. It can send an OBD-II serial bus message which can command the windows down.

A more remote possibility is a DCM module issue. You can try swapping the two doors' modules to see if the problem moves to your driver's window.

Keep us posted. This is not a common fault you've got.

Todd

Sep 23, 2011 | 08:13 AM

DBLTRGR

Thread Starter

Racer

Joined: Apr 2011

Posts: 254

Likes: 0

From: Great Falls MT

I don't believe it started after any particular repair, but because it's intermittent it's hard to say for sure. Nothing involving the doors though. I don't have a fob for the car and it doesn't happen when opening or closing the door. It happens sometime when I turn the key on, while driving and even once with the car idling and me standing next to it. It never goes up by itself and the drivers window works fine. I do suspect the door switch itself because that window used to leak in that area. I found corrosion on the connector to that switch. I inspected all the cables inside both doors and they look good. I like the idea of switching the DCMs (didn't know I could do that), but am now leaning towards replacing the switch. Oh yeah, taps and bumps haven't gotten me anywhere on this.

Sep 23, 2011 | 10:31 AM

toddk

Racer

Joined: Feb 2004

Posts: 359

Likes: 7

From: St. Paul MN

Thanks for the additional info. It sounds pretty intermittent, and may be hard to track down with a DMM. Too bad some tapping didn't identify the cause. Was there any corrosion from water in the DCM, or just at the switch?

Before swapping parts, a couple checks may narrow it down. I'm suspecting the DCM rather than the switch.

The up and down buttons short to ground when depressed in the door controls. An unintended short (or some amount of resistance) anywhere between those pins will be considered a button press by the DCM. The DCM expects to see near 0, and near infinite ohms.

The passenger side 7-in-a-row connector pin 5 is ground, 4 (light blue) is "up", and 7 (tan) is "down". You may want to check across 4-5 and 7-5 with an ohmmeter to see if you have any resistance when it should be open.

The DCMs can be swapped for testing, but they should be swapped back. Some functions may not work properly while swapped, but for window testing it has been used as a diagnostic.

One other approach is to just leave the passenger door switch module disconnected and see if the problem stops completely.

Todd

Sep 23, 2011 | 06:32 PM

DBLTRGR

Thread Starter

Racer

Joined: Apr 2011

Posts: 254

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From: Great Falls MT

Thanks Toddk and TEXHAWKO.
I tested across 4-5 and 7-5 and they are open. What I noticed is that the switch is corroded. I pulled the two bulbs and it's a disaster inside, so I've ordered a used one off Ebay. I haven't had this car long, but it's an electrical nightmare. The right headlight has a mind of it's own and I have the hot side, cold side HVAC problem (except when it's hot on both sides with the AC on which changes whenever I disconnect the battery). I've been trying to reset it by pulling the #27 fuse, but without luck so far. I fixed the wiper parking problem (thanks to this forum) and have gone over 9 of the 13 grounds so far. I'll just concentrate on this window for now and see how it goes. Other than that I LOVE THIS CAR!

Oct 4, 2011 | 11:41 AM

DBLTRGR

Thread Starter

Racer

Joined: Apr 2011

Posts: 254

Likes: 0

From: Great Falls MT

I got the replacement passenger side window switch installed and all is good now. Out of curiosity, I cut the old one open and saw the corrosion inside. It's a wonder the switch worked at all! I also R&R'd the dash yesterday and replaced the right side temperature actuator. The job wasn't as bad as I anticipated, thanks to a great thread on this forum on dash removal that included photos. Thanks!