help with wiring problem

[vett1954]

I have a 1990 coupe. I am having a problem with the dash and a/c control. When i put the key in ignition, dash display and a/c control work normal . As soon as i start the engine , the dash goes crazy and a/c control does not respond. I have replaced the ccm module last year and checked all the grounds that i could find. I was driving on interstate when this probl;em started right out of the blue. Any help or thoughts on this will be helpful . Thank you

 

[Paul Higg]

Hi and welcome to the forum!

It sounds like something is loose. Think about what you said. It is fine with the key in the ignition, (by that I mean turned to the on but not run position?) and when you start it up it does that. It sounds like when the engine is running, a vibration might be making a wire or terminal or ground go intermittently open. Do you have a factory service manual, better known as an FSM? I have a 94 so I do not know if the wiring diagrams might be related.

Another thing to think about is corrosion. If it spent its life in New Hampshire (I used to live in Boston but I'm okay now :L) and if it was anywhere near the coast the salt water in the air can raise riot with electrical contacts.

When you say dash do you mean the speedo display? Or something else? See if there is something related.

I would try to do as much as I could without tools first. For instance, you could remove the fuse for the A/C control and see what happens.

Best of luck and keep us informed.

Paul