[WMS]

Greetings and I need help. '92 Olds88 3.8 w/ auto. AC quit (blowing hot air). Dealer said compressor leaking. Replaced compressor and converted to 134a. When adding 134a cluch on compressor never engaged. Just like the original problem. Checked +12 on cluch plug...nothing. Should have done that before replacing the compressor. Traced wire back thru harness to relay. All fuses good, all relays ok, continuity on wires ok. Just don't get 12 volts to cluch. When I add 12v cluch engages and I get cold air. Jumpered connector for high and low pressure but cluch still not engaged. What am I not seeing. Got to be a sensor, switch something. What tells the cluch to engage and release. Help!!!