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1999 Ram Van 3500 Wipers don't work


bignoisey
04-17-2011, 06:17 PM
After sitting for several months unused, I drove it and needed the wipers, but they did not work. Checked the fuse and it was good. Checked voltage at the 4-pin plug on the wiper motor and +12V on all 4 with the switch in the fast position while the plug is connected. Checked the same plug while unplugged and found +12V on 2 of the 4 pins. Replugged the same plug and grounded one of the pins and the wipers operated for about one cycle then the fuse blew. So I think the motor is good, but there must be a wiper delay circuit somewhere that is suspect. Does anyone know where I would find this circuit? Any other ideas?

alloro
04-18-2011, 10:27 PM
the wipers operated for about one cycle then the fuse blew.

This is a fairly common symptom of a bad motor.

Mopar_Stev
04-24-2011, 07:14 PM
This is a fairly common symptom of a bad motor.

If there is good power to the motor and it isn't working, then the old wiper motor brushes died or became contaminated on the contacts. Alloro is right, replace the motor.

If the motor works when powered and no linkages are connected, lube the links and check for obstructions.

bignoisey
04-26-2011, 08:30 PM
Well we went anyway without wipers. Rainex works pretty good when its freshly applied, and the rain stopped aftrer a while.
As for the fix, since a new motor is almost 100 bucks and I'm a cheapskate, I dug a little deeper. The motor is easily opened once it's removed from the vehicle, Everything looked pristine inside. I also noticed that the motor gets its ground through one of the mounting bolts. The rubber anit-vibration grommets electrically insulate the motor chassis from vehicle ground except for a copper strap on one of the three mounting bolts. Just for grins, without it mounted I plugged it in and grounded the motor chassis through a test lead. It worked perfectly. Turns out the bolt that is supposed to make the groud connection was somewhat corroded. I cleaned that up and put it all back together and presto, its working. Those bolts thread through the panel into the area where the wiper linkage lives and thus are exposed to the elements at the top ends. Rain water must have seeped along the threads and eventually corroded the threads enough to break the ground connection. Chrysler should have wired the ground through the electrical connector. So I wonder how many perfectly good miper motors have been replaced without the owner knowing that just moving the grounding bolt would probably have fixed it. :smile:

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