Did a motor rebuild and know all my wires and connectors are hooked up, checked both grounds on each side as well.

My a/c compressor wont kick on unless I ground the relay on a blade. And my obd port wont register a signal to scan the car, says check for open ground.

Anyone know if these two could be related? and anyone run into same situation after motor work and have an idea where to start?

Dont have a wiring diagram around here, if someone could point in that direction maybe can figure it out.

 

What year is your car? Why not add a "signature" with basic info about your car.... year, model, engine, tranny and any major mods. Provides people with all the info they need up front to help you.

Are you saying the scanner will not connect? Are you using the correct OBD ( I vs. II)? Did you check the cigarette light fuse, which powers the ALDL connector?

 

95Z lt1 automatic, not my car, my cousins. Going to try and reach the a/c plug and see if the connectors got pinched or pushed back, the simple stuff first. Fuses are all good, as are relays. Ground the relay and it comes on, so its a open somewhere.

 

Oh and obd service port registered, my cable was bad, tried it out on mine and my wifes car and all said it wouldnt register, so knew something was wrong. Borrowed a friends Matco cable and its reading fine.

 

If the a/c system was discharged/recharged you might need to reset the PCM to allow it to engage the compressor.

 

Shoe box, your'e talking disconnect negative battery terminal for 5 minutes right? If you mean reflash, never heard of that to recharge an a/c. All I did is discharge it and disconnect and seal it while we pulled his motor and rebuilt it.

 

if you havent recharged the system, or if you have the wrong amount of R-134a in the system, the pressure switch inhibits the compressor clutch from engaging.

 

I drew a vacuum to get moisture out and let it hold for 1 hour to look for leaks. Started it up , put on high , full cold, added about 8=10 ounces , pressure got to around 28-30 but compressor wouldnt engage.

It all worked fine prior to tear down and kept it sealed. Its buiding pressure so the compressor should kick on. Even a minor leak will allow it to cycle, but it held vacuum fine. No kinks in lines, nothing hooked up wrong, no wiring cut or moved. Only part of a/c wiring that was touched was unplugging form compressor and pressure switch.
Will try the reset and see what happens.

 

Removing the PCM BAT fuse is a lot easier. 30 seconds is all you should need. Reset is what I said, not reflash.

 

Pouring rain here now, will give it a shot, makes sense.

 

May not be it, but it is easy to try.

Hey, I bet the guy in this thread would pay you big bucks to come work on his car.

https://www.camaroz28.com/forums/sho...d.php?t=667113

 

Shoe- I actually sold my shop in Jan, got diagnosed with lymphoma, my cousins car was last thing helping on, did alot for him as a graduation present to being a police officer. I mostly did older restos pre 74, but last couple years did alot of modern stuff as well, and after buying my Formual got into doing LT1 mods and LS1 stuff.

This car of his turns out to be the golden rule I overlooked. Always check aftermarket add ons and see if someone rigged the install. Sure enough, they tied an alarm into a major ground in harness, then my cousin had problems with alarm so disconnected that wire that was tied in, he didnt know, and it made an open. Plugged it all in after testing each end, and now its all good to go.

I feel for the dude in the thread, and if I was still at shop would have defintely not only gone through the trouble of right diagnosis first time, but no where near the rape charges he got. Hell for 3900 he could have added 5-800 more on a slow month for me and I would have rebuilt the motor with a few improvements including labor.

I will email him some people I would take my car too, or if he is handy with tools he could come over and do alot of the work with supervision. Head jobs arent horrible in those cars, but if your weak and sick, its a b**ch leaning over lifting them out and moving crap out of the way

 

That would be a right friendly thing of you to do. Hope your future holds some better luck.

 

My car had the same problem and I had bent one of the connectors on the compressor over when plugging it back in.