Two Electrical Issues

[tim71]

As I put my truck back together I have encountered 2 issues:

1) I replaced my original gage cluster with a new one that has a tach. The tach seems to work OK other than it bounces around temporily when you change the fan speed on the heater/ac blower motor. I'm using the original wiring harness, so tach wires are not associated with the harness at all.
2) With the AC controls in ac and temp on cold, shouldn't I be getting current at the plug that plugs to the compressor? I've been testing with a tester/light and I get nothing. Tested with fan speed in different positions.

Trying to solve any gremlins I can while it's still relatively easy to get to everything. I would appreciate any input.