So the previous owner of my 88 Iroc wasn't the sharpest knife in the drawer. He rigged up a manual fan swith that went from a blank spot on the fuse block under the steering column. It went to a relay under the hood, got power from the battery and was grounded. It stopped working after a power cable for my amp was installed We were trying to figure out the problem by seeing where the weak link was. Well, we figured it out, but now the gauge cluster doesn't appear to be working right. The tach went backwards and sat at 7000. The car starts and runs fine but the gauges seem screwey. The previous owner didn't wire in a fuse for his little switch, so I don't know what blew. Any ideas?

 

The tach is an easy fix...just remove the trim bezel and the clear plastic lens; the hardest part of the repair is using your finger to push the needle back around counterclockwise to somewhere in the 0 to 2000 rpm range. Test before re-assembling the lens and trim piece.
What else is acting up?

 

I'll give that a try, but the tach still doesn't work when the car is running now. I'm worried that because the fan switch was just a bare wire plugged in to the "acc pwr" fuse spot without a fuse. Did something higher up the chain blow as well and is there a fuse that covers this fuse block? Does that make sense?