I have a low mileage california sunbird covt. AC was converted 5 years ago to 134a and car is quite nice...issue is AC will not engage. I did the simple check of the heater/ac fuse and jumping the pressure switch and no clutch engagement. System is charged. Where is the relay? how do you trouble shoot? is there something else that is common? Thanks all...

On the 4 cylinder models the ac relay is located on the driver's side firewall... right next to the power brake booster and master cylinder assembly. The relay is under a thin plastic shroud that is mounted against the firewall. The relay you are looking for is the one on the right with five prongs and an electrical path on the side of the relay. Hope that helps.