70 SS gauges. I can't seem to figure out why the tach and ampmeter gauge lights aren't working. All the other gauge lamps work fine. I've switched lamps,tried known working good ones and tried new ones,but they still don't work.Are these two gauges on a separate circuit on the printed circuit?

do you have a good ground to these lamps

Just on expand on Tom's statement. The two tach lights and the single amp gauge light all share the same ground trace on the circuit card. The trace makes contact with the cluster metal back through the screw next to the top tach light.

I had my entire dash out, rebuilt the clock cleaned and freshened up everything and reinstalled it. There are 3 back ground wires on my harness (70 SS). I put everything back the way it was fresh, clean and tight. Still no amp-meter gauge {I have the actual gauge, not a light} after replacing the battery, alternator and rewiring the location where the external regulator used to be, 3 different times I was beginning to get a little upset. On a whim I pulled apart the main connection to the fuse box cleaned all the male and female connectors gobbed it up with some dielectric grease and “presto” amp-meter works all the lights on the car were brighter and the radio noise was gone. – Something to consider.

Thanks for the good info guys:
I'll check that ground screw first.The amp gauge and tach work,just the lights don't. Then I'll clean up the connector and see if that helps. :cool:
Thanks;