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Help! Blown oil pressure gauge, now it looks like a sh.ort...

Discussion in '80-Series Tech' started by dclee, Aug 26, 2006.

  1. dclee

    dclee

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    Just some quick help diagnosing this.

    For a while now I've had a blown oil pressure gauge. It's pegged on High, even with the ignition off. Weird. Replaced the sender, no change. So I figure it's got to be the gauge. Bought a new one from CDan, and ripped apart the dash today. Well, it is the gauge. There is a metal arm / gauge needle arrangement wrapped in the +/- wires that apparently come from the sender and then go to ground, variable, which when energized, cause the arm to move, and thus the gauge needle. However, mine was stiff, the arm was stuck in one position. Blown gauge. No problem, swapped in the new one, good to go. Then I noticed that the metal arm on the bad one was discolored, as if from heat. Since it is wrapped in those wires, this leads me to believe that a power surge heated those wires, and also blew the arm/needle assembly. I.e. short circuit. Although, the very thin wires themselves were not fried (that I could see).

    So, my question is, does anyone think I'm off base, and that it's not a short, and just slap the gauge pod back in? Or if it is a short, where the heck do I start tracing this? I have no idea which harness this disappears into, or where it goes.

    BTW, also replaced all the gearshift selector bulbs while I was in there. I have a lit "D" again! :cheers:

    TIA,
     
  2. landtank

    landtank SILVER Star

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    If it was a short I would think that it would be from the gauge to the sender. I would get a VOM on that line at the sender with the guage hooked up and look for continuity prior to starting he engine.

    Most of these senders work by lowering the resistance to ground as they detect a higher reading. So a short would be pegged at the top if it were like this.
     
  3. dclee

    dclee

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    Thanks Rick! I figure if the power was getting to the gauge, the short must be on the ground side. Anyone know where this harness goes through the firewall?

    TIA,
     
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