I can't seem to get my tach to work. Other symptoms include no a/c, no cruise control and a rough idle at initial start-up. I initially suspected the OVP, but have tried a couple of used OVP's I was told were fine with no improvement. Then I tried a used Klima I was told was OK, with no improvement. Lastly, I found the connection to the rpm sensor to be badly corroded and replaced it with a new Beru unit. Unfortunately, the tach still does not work.

Where should I go next? Should I look at the ELR Relay? If so, where is it located (I thought it was near the battery, but couldn't find it)? Should I test the wiring? Is it likely the tach gauge could be bad?

By the way, I have a multimeter, but am a novice with its use.

Any help would be very appreciated.