Expert: Roland Finston - 10/28/2011

Question
QUESTION: Hi Roland, I have a '99 Dodge Grand Caravan and the driver side power window will intermittently have trouble with the window going down.  It will sometimes work fine, sometime squeal for a few seconds and then nothing, squeal for a few seconds and then work, and sometimes does nothing at all. I will keep pushing it and eventually it will work again but it may take a minute (too long at a drive-thru.  It always goes up just find and the passenger side window has had no problems at all. Some knowledgeable friends say it is almost always the regulator that's the problem, but the symptoms make me more suspicious of the switch. I don't have a lot of money so I thought I would get your thoughts before I spend money on the wrong item. Thanks for your help. Gus

ANSWER: Hi Gus,
I haven't had feedback about which might cause this, the regulator or the switch. But I would start by testing the switch' up-down continuity which you can do without removing the entire trim panel to get to regulator mechanism. Trick here is that there is an express down function for that window so there are two ways to put it down. Does it work poorly in both the regular down and the express down mode? There is a 'module' for that express function as part of the switch and it appears that both down commangs have to pass through that module which is what makes be be suspicious of it as the source of your problem.
To test the down function you have to have a couple of jumper cables (light duty will suffice) to apply 12v to pin 9 of the switch (which you can get from pin 9 of the plug by a jump, and you must similarly jump from pin 13 of the switch to pin 13 of the plug). Of course you begin by removing the plug from the switch, and then do these two jumps, and then put the ignition switch in the 'run' position so that you are indeed getting 12v to pin 9 . Then you would measure with a continuity tester or an ohmmeter to verify whether there is good contacts (0 ohms) between pins 11 and 6 of the switch when you try the regular down and between 11 and 6 when you try the express down. If the connection in significantly different from 0 ohms or is flaky between 0 and infinite ohms then that would say the switch is the cause of your problem.
To remove the switch you need to:
remove the screw for the door assist handle (if equipped with that handle)
remove the screw for the door pull cup (if equipped)
Using a soft stick remove a cover from the switch panel that hides a screw
Remove the screw that holds the switch panel in place, then unplug the switch plug from the switch.
(There are a couple of other steps I omitted because I don't believe they will be necessary to get the switch panel off. If something seems to be preventing you from removing the switch panel let me know.
This is my best suggestion as to how to proceed to test the switch for the down commands. If that looks ok I will tell you how to remove the trim panel to access the regulator so as to lubricate it.
Roland
PS Please 'rate' my answer and consider a 'nomination' of me for 'volunteer of the month'. Thank you.

---------- FOLLOW-UP ----------

QUESTION: Hi Roland,

I had to work overtime for the last few days so I didn't get a chance to work on the van until tonight.  I am not sure I am clear on something. In your response you said:

"Then you would measure with a continuity tester or an ohmmeter to verify whether there is good contacts (0 ohms) between pins 11 and 6 of the switch when you try the regular down and between 11 and 6 when you try the express down."

Did you mean to say a different combination of pins (like 11 and 5) or should I be seeing a different resistance measurement when pushing the "express down".  Or maybe I am just really confused.  Please let me know.

Thanks, Gus

Answer
No, I did mean for you to check the continuity between 11 and 6 for both the regular down and express down mode. Be sure that you have jumped 12v to pin 9 and that 13 of the plug is connected to 13 of the switch (the ground connection) so that you are replicating the situation when you have it plugged together (though of course you can't do the measurement if it was plugged together.