This is probably related to my AC problems in the 300TD.

I decided to check the voltage at each terminal of the #8 fuse (AC compressor/blower, etc) against ground.

Voltage at the firewall side was ~12, but voltage at the other side (front of car) was variable and ~6. Also, that terminal was VERY hot. I replaced the fuse, and got a stable voltage ~12, but the terminal was still very hot.

When I have the AC engaged at the head unit, there is no voltage at either terminal lead to the compressor. The Blower motor (on the same fuse) works fine.

I have tried 2 head units, and the result is the same, so I don't think it is a problem there.

What should I do next - could this be due to a bad AC cube relay? ShouldI unplug the blower and see what happens?

Electrical gremlins are my worst automotive nightmare.

Help!!!!!

EDIT: Also wanted to add that there is definately a short in the tach - sometimes it registers rpm and sometimes it doesn't. I have read some linkage b/w tach and AC - could this be related?

__________________

Current Mercedes
1979 maple yellow 240D 4-speed

Gone and fondly remembered:
1980 orient red 240D 4-speed

Gone and NOT fondly remembered:
1982 Chna Blue 300TD

Other car in the stable:
2013 VW Jetta Sportwagen TDI / 6-speed MT