Hope someone can give me idea of where to look on my Explorer for trouble. It is 96 Limited with 5.0 V8 and has the full "Climate control" type of system. The thing has always worked fine (had to replace the expensive and unique fan resistor once), but all of a sudden the unit will not turn on A/C compressor. It figures it does this right when it is getting hot and humid outside. I checked refrigerant and it is OK. I jumped pressure switch at dryer and no go, I ran power and ground straight to compressor and it fires right up and air blows cold like it should. Tried volt meter and test light at plug to compressor and it reads no power. I know the truck has temp sensor inside for when switched to "automatic" but that seems to just control fan speed more than anything. Does the climate control unit in dashboard (with the switches and digital readout) have control for turning on compressor or is there something else that would do this. I do not have manuals that get into the details of this thing and hate to just buy parts (even at salvage yard) that are not needed. Odd that it just decided to quit overnight like this. But I am thinking the dash module may be the main control and hoped someone out there would have seen this before. Only other issue that may be in play is when you floor gas it will shut off A/C compressor so that is other possible problem. Pressure in system is good, jumping sensor took it out of possibilities, and compressor works fine if direct wired. I hate to Mickey Mouse this and wire manual switch to compressor. I love this gas hog and want it right. I hope to be buried in it (just had 39th major surgery and this time it was cancer) so that day may be sooner than I hoped. Does anyone know if the dash climate unit is direct control for this or is body computer or some other power system possible culprit? Any ideas would be appreciated.

 

I wold ck the compressor relay and also ck for codes in the climate module .

 

Keep in mind that your system has 2 pressure switches on it, one for low pressure cutoff and one for high pressure cutoff. Did you check the pressure with a single gauge or were you monitoring the high and low side pressures at the same time?

I'd suggest checking the inputs to the WOT A/C Relay in the Power Distribution Box to see if you have voltage to terminal 30, voltage to terminal 85, and ground to terminal 86 when the A/C is turned on. Whichever of those does not have the appropriate signal will help you determine the correct path to continue troubleshooting.

-Rod