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How do I test if the idiot lights are working?

mustang960 ยท 2010-05-12 12:10

Hi guys, I recently bought a mustang 960 with a million hours... the hour meter and fuel gauge don't work (which is obvious), but how do I test the idiot lights for the engine temp, hydro temp, and oil pressure? I have found all of the senders/switches, I thought that by simply grounding the wires to senders, the warning lights should come on. Is that true? Havent really played with the machine yet, but everything mechanically appears to work just fine...

Replies7
  1. #1tylermckee2010-05-12 12:50

    drain the oil and coolant and run it for a while :tong

  2. #2Sandhills-elect2010-05-12 13:14

    I think if they are jumped together that would complete the circuit and the light should light. But i could not say for sure that is how it is, but only makes sense. Good luck Brent.

  3. #3RHINOS TRANNYS2010-05-12 21:19

    Pull the wire off the sender units and short them to any metal part. It will make a ground and if the light and the wires are good the light will come on.

  4. #4mustang9602010-05-13 15:12

    Thanks Rhino, with that I've discovered the lights work fine, now how do I tell if the senders are working? The senders go to ground during a fault right? Like lets say I'm going to test the oil pressure switch, it would only go to ground (and complet the circut) with low oil pressure, like if the engine is not running? So if I do a simple test, with the engine not running, comeing from the positive side of the bat to the oil pressure sender, it should light the test light? right, and likewise, if the engine is running and pressure is good, is should not light the test light...am I on the right track?

  5. #5RHINOS TRANNYS2010-05-13 22:10

    You should be able to check senders with a ohm tester. Touch the prong and the outer part of the sender there should continuity. Thats on the heat temp and oil senders.

  6. #6RHINOS TRANNYS2010-05-14 21:53

    I am brianless. There is no continuity on the temp sender unless it is hot. Sorry for the wrong information.

  7. #7mustang9602010-05-15 12:09

    Yea I got ya now, was scratchin my head there for bit, but I think were on the same page now. I can't really test the water temp sensor without the water being "too hot" when the switch has continuity. I cant test the Hydro temp without the Hydro being "too hot". So really the only one I can check is the oil pressure, which should have continuity with the engine off and no pressure. If so, it doesn't work either...