The a/c system works when power is sent directly to the compressor ... but does not engage when the dash switch is depressed.

With the help of my dad & the FSM we spent a little while troubleshooting the switches/plugs/etc.

Everything seemed to be working correctly according to the volt meter until we got to the a/c amplifier.

This is the page from the FSM with the appropriate items highlighted. At the very bottom where is says:
"If circuit is correct, replaced the amplifier"


Does that mean if ANY of the conditions are true? or ALL of them?

the 5-7 & 6-7 were NOT true ...



Below is the wiring diagram with the 5, 6, & 7 wires traced to their origins.



Where do I go next?! Any advice is appreciated, I'm not too electrical savvy, but any info will be passed on to my dad Now that I know the rest of the a/c system is good ... i just want it to WORK!



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Has anyone been able to figure this problem out? I have the same issue, no power to the #6 terminal at the amplifier, from the top diagram. If I add a hot wire to it, the copmressor works...

 

looks like #6 terminal is the ignition wire, may have a bad wire. see if you can locate the wire at the coil end and check there.

 

After weeks of not being able to find the problem, I admitted defeat and ran a jumper wire from the A/C button on the dash to the A/C compressor. So, I now have A/C that works off of the A/C button on the dash. I have tried EVERYTHING, changed every part and harness that can be changed. I am no where near a solution for this problem..... Something is missing or?? I added the A/C system from another 4runner to mine, as mine came stock w/out A/C. Evacuated the system, proper charge, changed amplifier, checked cont. thru pressure switch, checked all fuses.......

 

SO, have there been any negative affects to the A/C system or the car in general from the jumpering? I am trying to figure out my A/C issues as well... similar problem.

 

Background: I installed A/C into my 1988 2WD pickup 22R-TE (originally no A/C) from a 1987 4WD pickup 22R. After replacing the correct 22RE-E/TE evaporator harness (different between the 22R and 22R-E/TE, I had issues with the A/C amplifier activating the A/C clutch too.

The first thing one needs to know is that the wiring diagram is wrong in regards to the A/C amplifier connector, so if you like following the diagram and looking at the A/C board, it will not make any sense. The test conditions for the A/C amplifier connector is correct. Pin 6 in the diagram is correct, however, one needs the voltage there, since this feeds the A/C clutch RPM activation circuit. The clutch will not active if the RPMs is too low, and will not if pin 6 on the diagram (pin 5 in the test conditions) is not correct. One can lower or raise the activation rpm by turning the knob marked RPM (the relay will click if activated/deactivated and do the same for the A/C clutch). Pin 7 in the diagram (pin 6 in the test conditions) is for the VSV. It is not required to have the A/C working; however, it will not raise the idle rpms. No voltage means that the VSV is open electrically (that was the case for my 1988 4Runner 22R-E). Hope this helps.