Hello all, I'm new here (and I'm no mechanic) and I bought a 1990 Iroc-Z Convertible in May this year. When I bought it, the Speedometer didn't work and the power mirrors and door locks did. Now they don't (well, the speedometer still doesn't ;D). In the fuse box, there's a marking that says "PWR ACC" pointing to a 30A circuit breaker. I'm confused... how can I make them work again? Thanks for your help.

Also, if you want to go above and beyond and help me with the speedometer, it would be greatly appreciated. It randomly works by shooting up to what speed I'm going and then, after a few seconds, it drops straight to 0 and turns on the check engine light. I got my neighbor to run the codes and it's codes 24 and 42. Thanks again!

 

check the acc fuse on both sides with a meter, and you will have to read the breaker with an ohm meter, pulled out. the mirrors arent listed but i imagine it comes from one of those too.

as far as the speedo, 24 means vss open circuit which means somewhere along the vss wire is opening up whether because of bad connector, loose wires, pinched wire, etc.
not sure about 42 but the bypass refers to the wire you have to disconnect to set the timing on a tbi engine

 

The 20A fuse marked ACC is blown. I don't have an ohm meter at the moment, but when I get one I'll test it.

 

did it work after you replaced it?