Temp and Fuel Gauge don't work

And this will help on the gauges not working issue:
http://www.wps.com/AMC/dashreg/index.html

A 63 Classic is shown, but this applies to any car with an external regulator. A Gremlin/etc. with the regulator built into the temp gauge can be fixed this way too, but you must take the gauge apart and solder wires to it to come out to the regulator. A bit more work, but if the points are bad or get corroded again after cleaning (as described above) this is a permanent fix. Well, more permanent -- the regulator can go bad or wires come loose. The regulator has to be grounded, but the gauges don't draw enough current to worry about mounting it on a heat sink. I've been running a similar setup since 1999 with no problems at all.

Thanks for your excellent explanation BUILD. Yeah, there are two electrically heated springs inside the Grem/Hornet type temperature gauge. As I understand it... the input voltage from the (yellow wire to instrument cluster printed circuit panel) ignition circuit supplies power to the first spring which has the contact points -they open and close, the spring-w-heating element calibrated to pulse around 5 volts, which then supplies the reduced voltage to the second electrically heated spring -that second one is the one that gets it's variable resistance ground from the sending unit (coolant temp send unit).

Yes; cleaning the contact points inside the temp gauge allowed voltage to 'wake up' my fuel gauge (as the temp 'CVR' supplies power to both the temp and fuel 'resistance readers'/gauges) but to my disappointment while both gauges began to operate, they both read to high because the 'CVR' spring is non-operational (it doesn't heat up and intermittently interrupt/open and close the points). So while I got them to work, they don't work correctly.

I'll be checking out FARNA's advice; to solder in some type of resistor to replace the burnt out factory 'CVR' (yeah, not really a true voltage regulator?)

I'm also interested to search for a replacement temp gauge unit that will simply swap into the factory instrument cluster. So far I've found an inexpensive Stewart Warner temp gauge that appears to have the same three stud mounting pattern but I don't know if it has the voltage reducer spring-w-contact points inside... yet

As for the Rebel/Matador/Ambo (and Jav/AMXs) temp and fuel gauges, they all have an external three prong 'CVR' that plugs into the instrument cluster printed circuit panel -it looks like a 1 1/4" x 1/2" silver metal box. -if you don't have a temp or fuel gauge, and you've already checked the sending units with an ohmmeter, that's what to check next? -see if it completes a circuit by touching those prongs with an ohmmeter...

The AMC clocks don't get voltage to operate from the reduced voltage dedicated circuit that powers the gauges -they get fused power directly from the fuse panel -either the fuse is blown, bad fuse connections, clock red wire is not plugged onto the fuse panel or the clock itself is failed? -usually a toasted/burnt/shorted winding inside the clock instrument itself?

I bet BUILD knows and can tell us how to wire or solder in a resistor, to bypass a failed factory 'CVR'... what type of resistor? where to buy?

Thanks all for patience and space on AMC Forum     

Richard, that is a three prong solid state voltage regulator, not a resistor. The CVR in the temp gauge is technically an "averaging voltage regulator", though it does in fact reduce voltage, it still maintains an average of 5V. The solid state regulator will deliver a steady 5V. The gauges don't care, they will tolerate a full 12V without damage, but of course won't work correctly (as will the sending units) as the variable resistance will be way off.

A voltage reducer won't work because the charging system isn't a steady 12V. With the alternator or generator running voltage will fluctuate from 12V to 13.5V, and may drop below 12V depending on battery and charging system condition (and can go over 14V). So if you used a 7V reducer to get 5V from the 12V system it would be off a good bit at any given time. A regulator maintains a specific voltage regardless of input, though input must be higher than output for it to work. The old averaging CVR needs at least 10V to work correctly IIRC, but the little 7805 solid stat regulator only needs about 7V to work, but will tolerate something like 18V... IIRC. It will take anything a normally functioning alternator will dish out.

I'm wondering if the suppressor actually failed or just by removing it you cleaned the connecting pins allowing your jumper to have a clean connection. That suppressor probably had been touched since it was installed about 44 years ago and some corrosion might have built up between the pins and the suppressor. But, you got the gauges working again which was the task you wanted to accomplish.

Now you need to check the radio! If you use a modern FM radio you may not have a problem without the suppressor. If you still use the old original radio (AM or AM/FM) you might. You can get radio frequency interference (RFI) suppressors that go onthe alternator output. If you've upgraded to a GM style alternator it may not even be needed.