Elexwiz

I spent a couple hours troubleshooting my a/c compressor. I used these wiring diagrams from autozone but I'm still stuck on the a/c clutch relay. All my relays are brand new, installed in cleaned sockets, with dielectric grease. I tested each relay in the e-fan jack and shorted across the temp sensor plug to test them. They all work. All my fusible links are good. I cleaned each socket with electrical contact cleaner and some emery paper wrapped around a small terminal soldered to a nail.





Here's where I'm at. Looking at the first wiring diagram (diagram 18) you will see that when the key is ON you have 12 volts through the fuel pump relay which goes to a lot of places. The a/c power goes back up to the right on the diagram. Yes, the fuel pump works. I can hear it start when the key is turned on and she runs normally.

On the second diagram (Diagram 16) you will see that when the a/c controls are in one of the a/c positions you have 12 volts running down through the low pressure switch (which I temporarily shorted across for troubleshooting purposes) and into one side of the a/c clutch relay (follow the 4.0 line). I removed the relay from the socket and shorted across the two pins (colors LT GRN and ORG) and the e-fan started and I heard the compressor clutch click.

I know my problem lies with the other side of the relay coil. Diagram 16 says the other side goes to "ENGINE CONTROL SYSTEM". I'm assuming this means the computer. If you look back at the first diagram (Diagram 18), the ENGINE CONTROL MODULE is on the bottom. The 8th pin from the left, on the top of the ECM, is a BLU/WHT wire that goes to the A/C SYSTEM, pin# A12/202. I'm assuming this is the same wire that runs to the bottom of the a/c clutch relay on diagram 16. It says the wire is a BLU/WHT wire.

My question is, what condition has to exist for this relay to be activated? The key is on, the environmental controls are on one of the a/c settings (I've tried all 3), and the blower is blowing. Once this relay closes, I'll be good to go! Thanks!

Elexwiz

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