Couldnt figure out an a/c problem. Anyone near Dallas take a look? 05 exp

[stephen4785]

I looked at Cannon's 05 Expedition this morning. It was a little low on freon so I evac'd/recharged the system so I could inspect for leaks. Compressor wont kick on. Low pressure switch has voltage, high pressure switch has voltage, clutch relay is not getting a ground signal from the ecu. Checked fuses and relays still nothing. Im thinking the ecu is lacking an input signal to ground the relay or the driver in the ecu is bad. Only scan tool I have is a snap-on brick that goes up to 2002(really need to invest in a new one).
Anyone near Dallas able/willing to help him out?

[jackass racing]

gonna hafta get a wiring diagram and see which wire grounds the relay from processor...either a wire or processor

[stephen4785]

gonna hafta get a wiring diagram and see which wire grounds the relay from processor...either a wire or processor

Im thinking it's a processor issue but I wanted to see if anyone could use a newer scan tool to command the a/c compressor on. If you can command it on then the circuit is fine and it must be missing an input for the ecu's a/c condition.

[shumpertdavid]

there is a de-icing switch shown in the wiring diagram. Power and ground feed into it, then a signal comes out of the de-icing switch goes through the lower pressure switch, onto the high pressure switch and to the ecm finally. Did you try jumping 30 and 87 for the relay to make sure the compressor would kick in.