1990 Plymouth Grand Voyager Crazy Speedometer

My speedo just starting going nuts all of a sudden. When I am driving, needle bounces from 0 to 120 mph. Where should I start looking?

Reply to
Rob
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Speedometer sensor - It's on top the transmission, but you can only reach it from below. Remove one bolt, pop it out, wipe the oil off your face, and pop the new one in.

Reply to
Tom Bavis

This vehicle has a mechanical speedometer, the sensor does not come into play at all. A faulty speedometer would mean either the pinion at the sensor, the cable, or the speedometer itself is faulty. Of course, this did not come clear until after I purchased and installed a replacement sensor ($80) as the first step in troubleshooting, with no avail. In my case, it was the speedometer itself gone loco.

As reported, removing the cluster is really not that difficult. The trickiest part is the shifter wire. The wire controlling the shifter is removed by unclipping a metal retaining clip just under the steering column, stretching the wire, and sliding it out from the slit it is installed through. There is a little metal clip that is located just behind this slit on the wire, keeping the wire in place. You have to see this first hand to understand what is going on. Both large round plugs come right off and there is a third square plug on the right side. The speedo cable is also back there and may come off with a good yank, otherwise, the panel under the steering column must come off, arm shoved into the general area near the center of the cluster, and forced off, feeling your way around.

After I removed the cluster and took off the front face, I was able to remove the speedometer and inspect it. I inserted a small metal rod into the speedo cable hole and was able to replicate the crazy speedo performance (jerkiness, needle going to 125mph, etc). The odo would still not work. I then sprayed a good deal of electronic lubricator, this stuff is used for sliding switches and the like, doesn't harm plastic, and allegedly lubes. I sprayed it up into the incoming speedo cable area and all of the small plastic gears and voila, the "dinging" noise disappeared, the speedometer began behaving naturally, and the odo began to turn.

I put it all together and went for a test drive, put about 10 miles on it at various speeds. It appears to now work normally, with the exception that the "dinging" sound reappears occassionally at speeds above 45 mph. If this turns out to not work, I'll get another cluster or speedometer and put this problem to rest for good.

Thanks all for your help. I'll probably be back shortly with something else gone wrong on this vehicle, it is going to make a master mechanic out of me, it is.

Reply to
Rob

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