I have an 89 caddy deville that blows fuses(air condition fuse) every time i push the auto switch on the control,the controll unit has been replaced and it still blow the fuse went the compressor kicks on. I can not check the computer,because the fuse blows when i try. Any help out there!!!!

 

Blown fuses usually means too much current draw. I would check for loose grounds!!!

 

The excess current draw could possibly be the compressor clutch. Don't know how accurate this would be as a check, but you might try disconnecting the electrical connector to the ac compressor and see if the fuse still blows. An '89 is also old enough to have some bare wires, so you may have some detective work to do.

 

Many Moons ago, when I went to Lincoln Tech, I had an instructor tell me his process of checking for electrical shorts to ground hidden within the body. Although, I have never to this day been able to try this procedure, it was quite interesting. He would hook up a 30 amp circuit breaker to the fuse box on the circuit in question, then go down the body of the vehicle with a compass. He said the compass needle would shake back and forth as the 30 amp circuit breaker would open and close the circuit and where the compass suddenly stopped moving he would drill a hole into the body and look for the short.

 

NewHomeOwner,
That little test is used to also find a break in a underground pet fence wire. I've never done it either, but sounds feasible.