A couple of weeks ago I went to turn on the rear
wiper on my '94 Dodge Grand Caravan, and the wiper went up to about the
halfway point, and just stuck there. I had a good idea that the mechanism
was physically jammed, because it would "twitch" whenever it got the sweep
signal. Well I couldn't just leave it like that because there was no way
to to turn it off. It would keep trying to "park" the wiper back to the
home position even though the switch was off. So, I pulled over in the
rain and yanked the fuse (which turns on the AIR BAG light) until I could
get a chance to work on it.
Later that day I popped the hatch and went to work removing
the multitude of screws holding the plastic interior hatch panel. You have
to remove the speaker grilles also, as they hide a couple of screws, and
then there are a couple of wire clips that need to be pried loose. Then
there is a shiny steel plate that has to be removed. The wiper motor/gearbox
is mounted to the back of this plate. But first, the wiper arm itself has
to be removed from the outside. I lowered the hatch and looked at it, and
at first I couldn't figure out how to remove it. After placing a small
mirror behind it, I found the clip, slid it, and the arm was off in 2 seconds.
The arm has to be pulled away from the glass and held while sliding the
clip up. Finished removing the plate, unplugged the connector and unscrewed
the motor.
The motor looked brand new, but I knew it was original
because the mfg. date was 10/93. It was also clearly made to be replaced,
NOT repaired, because the gearbox part was riveted together. I took it
up to work and got my ace mechanic brother-in-law to help. BTW, he's not
an auto mechanic. First thing we did was drill out the rivets and removed
the access plate and of course the gasket ripped apart. After visual inspection
it was clear what the problem was. The motor has a worm gear on its shaft
that drives a nylon gear that's about 3" in diameter. The nylon gear has
an arm on it that drives the wiper shaft back and forth, not unlike the
driven wheels on an old steam locomotive. The metal shaft that the nylon
gear rides on had ridden up out of its mount causing the arm to jam against
it. I didn't want to just shove the shaft back down, because I knew it
would just ride up again. So we yanked the shaft out, and degreased it
and the cavity it mounts in and applied some Loctite to it and stuck it
back in. We removed the remaining gasket material and used some gasket
in a tube stuff instead and replaced the access plate. Now we drilled and
tapped the rivet holes and used 6-32 screws to hold it together.
Went back out to the van, replaced the fuse, turned on
the ignition, pushed the wiper button, plugged in the motor, grounded it
to the frame and........ It worked! I breathed a sigh of relief and remounted
it and put everything back. It's always fun when you fix something that
was never designed even to be disassembled. It's even more fun when you
save $120 for a new part, or more like $300 for the dealer to replace.
Plus it's one more piece of junk kept out of the landfill.
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