A/C added to non-A/C FJ60 (1 Viewer)

[msummer]

My '84 FJ60 had a dealer installed hackjob A/C system. I have since tossed all that and converted to the OEM setup. In general, this is what I have added:
- 3 groove crank pulley
- new motor mount arm
- radiator hose changes
- rebuilt compressor
- condensor/dryer/hoses
- under dash goodies

Today I took it to the A/C shop and had the system evacuated and filled with oil and R12. When the fan switch and A/C button are on, my idle up mechanism comes to life and the A/C button glows. Unfortunately, my compressor doesn't come on. The A/C shop jumpered from the compressor to the battery and the cold blew air.

I've read through most (if not all) the A/C related threads on here and can't figure out why the clutch isn't coming on. I turned the little knob back and forth on the A/C amplifier board but no change. Give me some ideas guys.

Matt

 

[pvidrummer]

Umm... Have you checked the a/c compressor relay???

 

[msummer]

My understanding was the A/C relay powers the whole system, including the idle up solenoid and button light. If that is right, then that can't be it. Am I wrong on this though?

 

[msummer]

Anymore ideas?

 

[beaufort-fj60]

there is a small fsm for the a/c

 

[fourand20]

there is an AC amplifier near the fan box underneith the glove box. if that is bad your compressor will not come on. do what i did. bypass that worthless crap and put a new switch somewhere on the dashboard and "hot wire" your AC compressor. all of the goodies still work when the compressor is on. ie...the idle up, fan ect.....
hope this helps......BTW, i replaced my OME compressor, then flushed and refilled my sys with r134. works just as good on a hot day..

 

[msummer]

What does the pressure switch in the evaporator do? Is it for detecting too little pressure or too much? Just wondering what would happen if you hotwire the compressor and leave it on for a long drive.

 

[bobperu]

If there is too little pressure in the system it won't send voltage to the compressor clutch. Mainly to protect your ac system. If there is too little pressure, oil will not be circulated and the compressor will not be properly lubricated. So, do not bypass the pressure switch. Make sure that the switch is operating properly. Also, if you want to save some money, skip using R-12, and use Freeze-12. Freeze-12 is a drop in replacement. I use it in my '82 FJ60.