Hi all,
I need help trying toget my kids AC up and going for the summer.
92 F150 w/5.8.
With engine started, and the AC on "max or normal" setting the compressor clutch does not engage, not even an attempt.
I threw a meter on the wires/plug going to compressor and nothing, no 12 volts, no measured charge on the meter at all - (engine running A/c on).
Now, if you haven't already figured it out I know nothing about A/C systems.
I have checked fuzes, ect. and everything seems to be in order there. Where should I begin to search for the problem.

Thanks for any and all help.

Robb

 

If the system is low on refrigerant the clutch will not engage. You can bypass this by jumping the low pressure cut off switch. it is the switch mounted on the dryer (black cylinder on pass firewall). Disconnect the wireing harness and jump with a paper clip, clutch should engage.

 

will give it a try, Thanks

 

If it does kick in and run, don't run it long with the jumper. That switch is to protect the compressor when the freon is low..

 

Have the system recovered and deep vac'd to check for a leak. The clutch isn't engaging for a reason, there isn't enough refrigerant in the system. If the low side pressure gets too low for an extended period of time the evaporator will freeze up, and the high side pressure will be out of control, possibly damaging the condenser or compressor. Don't try to rig it or anything, have it fixed correctly.


FWIW: being a '92, your truck originally came with R-12. Retrofit kits are available to convert to R-134a, however the oil and seals will need to be changed as they are not compatible.

 

I did jump the plug and the clutch did engage. So what now? Do I need to take this in and have it all checked out by a pro or can I get this thing working with a little elbow grease of my own?
Thanks
Robb

 

my truck is a 92 and it called for r12, however i pumped it up with r134a and i havent had a problem. i got the little retrofit things that screw onto the low and high pressure ports. you can get the retrofit kit and pump it up with r134a at your own risk. like i said, mine works great, but others have not had the same luck. they make r12 substitutes i think. the last one ive heard of was freeze12. your most likely low on refrigerant.

 

Does the system have any pressure at all? With the compressor off the pressure will equalize across the system, should be around 150 psi.

If you have little or no pressure you have a leak in the system. just fixed one today that had a pinhole in the condensor discharge line.

Has the system been retrofitted? R12 system has small service ports with threads on the outside, R134 system has 2 different sized ports with threads on the inside. R12 systems used mineral oil for lubrication, R134 sytems use Pag oil. Mineral oil is not compatible with R134.

To work on the AC sytem you will need a set of ac gagues, Vacuum pump, refrigerent, seals, dye, etc. It is probably 6's to buy the tools or to pay a shop. If you plan to work on many vehicles, buy the tools. If this is the only vehicle you plan to work on, pay a pro.

 

Retro fit kit, and a couple cans of R134, and a cheapy guage should do it. I've converted a couple vehicles and charged up with a single guage kit many times have had good luck.

 

did as suggested and the fuse blew clip melted in half so anyone know which fuse it might be because im not getting any air now ive checked all the fuses that have anything to do with ac and they are all good its a 2000 f350 7.3l

 

well found it bypassing that low pressure switch and clutch still not kickn in any other suggestions

 

Do you have power to the compressor ? I have seen a few that the wire is broken inside the compressor itself.

 

Well I broke down and took it in to a shop. They found the compressor was bad, and there was a leak too. Due to other issues with the truck and the shop wanting over $500.00 to fix just the A/C we opted not to have it fixed. We are settling on 2/55 A/C (2 windows down, 55 mph)
Use the truck for a year or so and try to move up to something a little better shape.

THanks for the help guys I appreciate it!

Robb

 

My 2001 f350 ac compressor clutch will not engage. I have voltage at compressor and it will engage if hooked to battery. Replaced connector for clutch. I have 35 lbs on low side when compressor jumped. Any suggestions I have also jumped high and low side switches. Need suggestions please