Rheostat "Repair"

The installation of Dan's wiring harness requires removal of the dashboard. When I did this for the first time about 7 years ago, I found that the rheostat had been bypassed. Seeing as everything else worked OK, I just left it alone. Now that I'm re-doing all the wiring I decided to a continuity and resistance test to see if it worked. Now I'm no electrical guru by any means but I figured a multi-meter test lead on each terminal would, at least, show continuity through the rheostat if it was working. When I didn't get a reading I figured I had nothing to lose by taking it apart. The late model rheostats differ from the newer ones in two ways: the back cover is "permanently" attached and the internal components are "solid state". The older ones have metal tabs holding the rear cover in place and the internal component is a coiled wire.

Back Cover Drilled Out Rheostat Interior


Once I had it open, I removed the
3 parts of it to clean and test.

As you can see in the enlarged picture of the three parts I almost wrecked the printed circuit on the back plate. I tried to use an eraser to clean it up and it started to come off of the plate. I taped it back down and tested the contact points for continuity and it appears to be OK.

Next up were the sweeper/contact arms

End view of the 5
 contact points

End view of the 5 contact points

The problem appeared to be simple enough: at least one of these arms wasn't making contact. I cleaned them up, bent them out more, reassembled the unit and now had continuity. I also did an ohm resistance test and got varied readings when I turned the knob.

Reassembling it did present one problem. The rivets that I drilled out weren't rivets at all. They were part of the case. I tried to drill them all the way through the case but decided to take the easy way out.

Oh well, no one will ever see it again

Now that I've done all of this I don't know if I want to risk hooking it up again, as I'd have to pull the dash again to fix it or re-wire it.