93 F150 5.0/e40d speed density.


Parts replaced: compressor,drier and orifice tube..
Parts flushed: condenser,evaporator core

Fuse #6 is good, one side of high pressure switch has power.
No power to either lead on the compressor clutch pigtail.

Have power at the heater control switch(off,vent,normal,max)

Where or what else should I check?

I looked on prodemand(Mitchell1) thanks to my job O'Reilly's for some diagrams but no luck, I might end up buying the Chilton book for some diagrams.

I really want to get my a/c working as it should. Compressor works fine when 12v is applied.

if i run it directly the pcm doesn't get signal to increase engine idle to compensate for the compressors drag and the engine stalls.




Picture of the truck

 

Have you charged the system and what did you refill it with: R-12 or R-134a? It would have originally been R-12. What are the pressures? If the system is low on refrigerant or the pressure is too high when running it won’t work without jumping/ overriding the pressure switch.

 

Not sure if your system is charged but On some vehicles after I have replaced a/c parts on I have had to “jump” the pressure switch(es) to get the compressor engaged to start charging the system. I use a light tester to find where power ends and simply jump that particular switch by unplugging it and bridging the wire terminals with a small piece of wire or metal paper clip. Done this for years without any problem but you really do need a wiring diagram. On Most of these older vehicles IMHO the a/c wiring is pretty simple.

 

My original post didnt save. So I wrote it again and left some info out.


If I jump the pressure switch it still won't come. I get power to one lead on the pigtail for pressure switch..

I have power coming to the ac panel.
System should have approximately 36oz of r134.

 

Not positive how yours is set up but there’s sometimes more than one switch. Look for one at the dryer, near back of compressor, near high side service port. Jumping them takes them out of the equation. So you’re left with a possible broken wire to trace out.
Also make 110% sure when you jump them that both sides then has power.
I should also mention that the fuse probably feeds a a/c relay. If so, you need to make sure the relay is closing to send power.