Messed up RPM Tach and AC

[stangtmb]

If anybody could help me, it would be great. I took my '92 5.0 in to get the ac fixed. The mechanic had my car for 3 days and still didn't fix my ac. He said he could not locate the AC Relay. I think it is the same as the wide open throttle relay. Anybody know exactly where it would be located?
Also he screwed up my rpm gauge. I know its some kind of electrical problem and it always reads at about 4,200 rpm. Any clue on how to fix that?

 

[TrickStang37]

thats a great mechanic you got there.

 

[Black1987Stang]

its on the passenger side hanging on the front side of the strut tower with a little screw, it has 4 wires.The wire colors are red, black with yellow stripe,yellow with blue stripe, and pink with blue stripe.hope this helps and i wouldn't bring it back to that guy again.

 

[HISSIN50]

also depending upon how late a 92 you have, there could be a FP relay near the WOT relay - just so you know. IIRC, the relays are the same part number.

the tach uses the neg coil signal.

good luck.