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Temperature idiot light on 76

Started by Denise 20352, August 31, 2005, 02:09:04 PM

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Denise 20352


  I ran my 76 for a long time at idle with the A/C on yesterday, and I noticed when I went back inside it that the yellow temperature light was glowing, very dim.  How does this work?  Is it a simple warning light circuit that maybe has a problem that is causing it to show up dim, or is the light supposed to get gradually brighter as the temperature increases, maybe?

  I had a Toronado that had a flashing temperature light, then when it got really hot, a metal temp light would come on and you had to pull over immediatly or suffer engine damange.  The Cadillac also has a metal temp light, but someone either switched the heads around or put the wrong switch in there, because the last time I hooked it up, it came on and the key buzzer sounded before I got down the block.  I think it has the switch from the other side that is supposed to turn the blower on.

  Anyway, with the metal temp switch inop right now, I need to have the other temp light working properly, so if something is wrong that is making the light come on dim, Ill have to fix it, or install a gauge.

thanks

-denise

Steve Preston #16375

Page 6-4 of the manual, which refers incorrectly to figure 12-19 (should be figure 12-22), explains this switch & light. Basically that switch shunts to ground the wiring for the Coolant Light. It closes contact to ground when the coolant gets to be > 260 degF.

To test:
1) The light should illuminate when you turn the key to the start position. There is a direct wire connection from the ignition to the light in the start position. This is a designed test of the circuit. Does it illuminate brightly this way? NO, probably the bulb. YES, go to #2.

2) Remove the wire from the switch, turn the ignition to the run position & ground the wire. The light should illuminate. If its brighter than when hooked to the switch, Id suspect the switch needs replacing.

Also check your voltage @ idle after a few minutes. Its possible that the alternator is weak. I replaced my Eldos alternator with a 100 amp for an 84 Eldo. However at idle for long periods with the AC on voltage output drops some. I have a $15.00 digital voltage meter that plugs into the cigarette lighter to monitor things. But even after long idle periods, it never drops below 13 volts.

The 12 +VDC power feed wire to ALL dash lights is a pink wire directly from the 5 amp fuse marked gauges in the right side fuse bank. Check you voltage on both sides of this fuse.

Let me know how these check out, Steve

denise


  The light tested OK, so I guess it is the switch or the wire.  Unfortunately, its about as easy to get to as the distributor hold down and the carburetor screws.

  I have to pull the compressor out of the way soon to take the intake off, so while Im in there Ill fix it, and maybe put a long union nut on the distributor so that I can set my timing.

thanks

-denise

Rusty Shepherd CLC 6397

The key buzzer you heard is also part of the engine metal temperature warning system introduced with the 472 in 68.

denise


  I think its a great idea.  I just need to get the right sensor on he head so that I can plug it back in.  Maybe I can just swap them around, or maybe the one from the 425 will fit.

  Or I could leave it this way and if the engine overheats, the blower motor will run, and when the engine is warm enough for the heater to work, the light will come on and the buzzer will sound.

-densie