Joe,
When you put the VOM on the amp meter you say "nothing" I take it resistance is infinity? and not a 0 ohms?
If you have access to the circuit two leads try series in your VOM on the amp scale, start high then come down on the VOM, this will make sure the current is flowing to the meter.
Maybe someone here has a GM Shop manual that can reference the correct resistance. I would think it is a wirewound resistor. Show you how dumb I am I didn't realize they used amp meters, I thought almost all were Volt meters.. :duh
There is a place called RedLine Gauges too. I'll look around and find his address and get back to you..
REDLINE GAUGE and CLOCK REPAIR (sorry no web site)
1-800-375-2310, attn: JOHN
Bud