so my AC doesnt work....it hasnt since i bought the truck about 5 months ago

anyway, im trying to figure out why now

the reason it wont work i guess is because the clutch will not engage....it engages fine if i manually jump it directly from the battery, but thats it. if i jump the low pressure switch...nothing. if i turn on the AC in the truck...nothing

the coolant pressure on the low end is acceptable, i havent measured the high end though....

there is no voltage from the connector that goes to the clutch...this one:



i would imagine why the thing wont engage. is it possible this connector is bad? i checked all the fuses and relays, they all seem to be fine

the only other thing that concerns me is this.....some of the wires for the AC connectors go into a harness connector, and wires from that go to another one which has NOTHING CONNECTED TO IT (i have it circled below. the AC connectors trace back to the connector on the right)




any ideas? im stumped

 

Power for the compressor clutch solenoid comes from mini fuse #1 in the underhood box. The PCM controls the clutch by way of the A/C Clutch Control Relay. It needs a couple of things to decide when to do that:

(1) There must be B+ on the purple wire from the HVAC control panel. This tells the PCM that the Selector Switch is in a user-selected mode where A/C is allowed.

(2) The Black/yellow from PCM pin 86 must be grounded. In order to have ground level on that wire, both the A/C Low Pressure Cycling Switch and the High Pressure Cutoff Switch must be closed at the same time.

 

E=mc2

 

Also see my other post at https://www.ranger-forums.com/forum2...ad.php?t=66138

Having the exact same problem here.

Dumb question: What would happen if you set up a semi-permanent jump between the battery and compressor, bypassing the relay, computer, and all the other crap that can go wrong with the electrical components of the compressor?

My assumption is that the compressor would run all the time, A/C on or not, and would rob power from the engine at times that it would need it -- like when towing and going up a steep hill. Is there any other consideration that would have to be made if I were to make such a dumb move? Perhaps adding a switch to disable the jump from the cab? >.>

It's really out of despiration -- I have a 22 hour drive coming up between California and Colorado in the middle of summer, and I wouldn't have the money to replace every little part that could be wrong with the system. I won't do it if it's going to cost the long term life of the vehicle. Advice?

 

You must leave the A/C low pressure cycling switch in operation. That will help prevent evaporator coil icing (which would take your A/C cooling efficiency to near zero). You also need the high pressure cutout switch to safeguard against the possibility of overpressurizing the system and blowing your refrigerant out of the pressure relief.

In short - don't do it. Have it repaired properly.

 

FYI

i had a melted wire heading to the EGR apparently, according to teh dealer

 

The EGR? I wonder what the gas recirculation circuit has to do with the AC? Weird.

 

The EGR vacuum controls are connected to the same vacuum tree as the A/C vacuum controls.