jmyers

iTrader: (1)

I have a 5.3 in my Sonoma but I am using all the original a/c equipment from the old v-6. My question is, I had a wire that went to the old ecm and now have no old ecm, not sure if the wire was an input or an output. Can I make this a/c system function without any support from the electronics? It could have been an input to raise the idle of the old throttle body when the compressor came on. One schematic shows a pin b8 off of the ecm that is labled "evaporator pressure control switch". Still not sure if it feeds the switch or if it recieves an input. If anyone has messed with something of this nature I would really appreciate some input. Thanks.

Rick Speed

iTrader: (55)

install a pressure switch in one of the lines and run the wiring to the new pcm.

BP Automotive

iTrader: (3)

If you are going to use the existing pressure switch that was on the 93 you can wire it like this. There is only one wire that goes back to the pcm. It is simply for the A/C status signal so the pcm can bump the idle and kick on the fans.

jmyers

iTrader: (1)

That pretty much simplifies it. Thanks BP