A/C compressor not turning on?
New User
Joined: May 2012
Posts: 14
Likes: 0
My compressor isn't coming on, it's a 87 lariat, it turns freely by hand, I put a gauge on it and it reads really high, which is weird because I've never added anything to it, the fuse is good, any advice would be nice
Post Fiend
Joined: Dec 2010
Posts: 10,121
Likes: 3
From: Orrville, Ohio
The gauge will read really high if the compressor isn't running. The gauge goes on the low pressure side and when it isn't running the high and low pressure lines equalize, so the low pressure side is high, the high side is low. There have been multiple people have issues with the plugs on the compressor. Make sure all the connections are tight. If that doesn't do it , then you may need to install a jumper in the high or low pressure switches to trouble shoot the issue. There can be issues as well with the clearances on the electric clutch on the compressor. There is a thread on here somewhere about removing a shim to make the clearances in the clutch what they should be. Let me see if I can find it.
Post Fiend
Joined: Dec 2010
Posts: 10,121
Likes: 3
From: Orrville, Ohio
Here you go. Check our post number 4 by Cuda_jim:
https://www.ford-trucks.com/forums/7...n-and-off.html
https://www.ford-trucks.com/forums/7...n-and-off.html
Post Fiend
Joined: Dec 2010
Posts: 10,121
Likes: 3
From: Orrville, Ohio
There are two pressure switches that could be preventing the A/C compressor from running. One is on the back of the compressor itself, the other one is in the line over near the passenger side fender. You can use a small piece of wire or (or a paperclip as long as you make sure it doesn't touch anything) and jump one wire to the other. You just need to connect the two wires together and you have bypassed the switch.
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Fleet Owner
Joined: Aug 2004
Posts: 20,419
Likes: 197
From: AZ
One more thing to think about before you call it low on coolant. The connector on top of the a/c compressor at the rear. It's a round 2 pin connector. That is a high fail part. Turn the a/c on max, high fan. Go out and wiggle the crap out of that connector. I bet your compressor will kick on.
If it does, the connection just needs to be cleaned and tightened up. You could take a chance and crimp the female connectors a tad, and hope for the best, you could replace the connector.
I just took the red lock out of the face of the connector, took a few 3/4 inch long strands of wire, bent them in a U shape, and put them in the female end hanging half in and out of the connector. Then reinstall the lock and it will hold the copper strands in place. That one strand of copper will make all the difference in the world, and you shouldn't have any more connection problem. Hope that helps.
If it does, the connection just needs to be cleaned and tightened up. You could take a chance and crimp the female connectors a tad, and hope for the best, you could replace the connector.
I just took the red lock out of the face of the connector, took a few 3/4 inch long strands of wire, bent them in a U shape, and put them in the female end hanging half in and out of the connector. Then reinstall the lock and it will hold the copper strands in place. That one strand of copper will make all the difference in the world, and you shouldn't have any more connection problem. Hope that helps.
Hope you get it going!!
Post Fiend
Joined: Dec 2010
Posts: 10,121
Likes: 3
From: Orrville, Ohio
The gauge won't read correctly unless the compressor is running. If you can add enough freon to make it run then you can get an accurate reading of what it is actually doing. Is it running after you added that one can?
