1986 AC C68 Question
Thread Starter
Burning Brakes
Joined: Jun 2003
Posts: 1,079
Likes: 1
From: Niagara Falls ON
1986 AC C68 Question
I finaly decided to get the ac working in my 1986. I put a new compressor on and charged up the system. I can't seem to get the ac clutch to engage. I wasn't sure if the C68 climate control doesn't engage right now because it is so cold outside or if there is something that I should be testing.
Thanks
Thanks
Safety Car
Joined: Jan 2004
Posts: 3,556
Likes: 13
A/c fuse good?
Have you got power on the dk green wire out of the clutch?
Clutch is turned on by being grounded at the blower control module ( operated by the head unit
which monitors the pressure switches)
Have you got power on the dk green wire out of the clutch?
Clutch is turned on by being grounded at the blower control module ( operated by the head unit
which monitors the pressure switches)
Last edited by vetteoz; Feb 25, 2012 at 01:39 AM.
Team Owner
Joined: Jan 2003
Posts: 20,297
Likes: 240
From: Summerland B.C. Canada
Some help from my 86 FSM
http://members.shaw.ca/dankai/HVAV'S.pdf
http://members.shaw.ca/dankai/HVAC%20Electrical.pdf
http://members.shaw.ca/dankai/HVAV'S.pdf
http://members.shaw.ca/dankai/HVAC%20Electrical.pdf
Thread Starter
Burning Brakes
Joined: Jun 2003
Posts: 1,079
Likes: 1
From: Niagara Falls ON
I will check the pressure and let you know.
Thread Starter
Burning Brakes
Joined: Jun 2003
Posts: 1,079
Likes: 1
From: Niagara Falls ON
The R134a that is in the system was sucked in based on vaccum. I know that the compressor is supposed to be on but that is what I am at...one can in the system based on vacuum alone. So yes, it is not fully charged.
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Le Mans Master
Joined: Dec 2000
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From: San Diego, Ca
It probably won't start with only a can (if you even got that much in it - hard to get the full 12 ozs sometimes).
Low Pressure Switch contacts need 50 psi to close and crank on the compressor. You might get that with what you've got in it, but it will drop well below the threshold for operation (25 psi) within seconds. You need to jumper the low pressure switch harness with a paperclip to finish up. That will get it running and it'll probably make a little ice until it sucks in the balance of the charge. Also, make sure the Main Fan is running by disconnecting the Fan Switch on the High Line. If you've converted to R134, use only 80% of the R12 charge and aim/stop when the high side reaches 2.5 times the air across the Condensor. When done, reset the Low Pressure threshold to 22.5 psi. Disconnect the Blower Motor with the system on Max and the low side will drop. Note the Low Side Pressure when the compressor cutsout. There's an adjustment screw between the Low Pressure Switch Terminals. Turn it clockwise to raise the threshold; counterclockwise to lower it - about a 1/2 turn at a time - until it's cutting out at 22.5 psi.
Low Pressure Switch contacts need 50 psi to close and crank on the compressor. You might get that with what you've got in it, but it will drop well below the threshold for operation (25 psi) within seconds. You need to jumper the low pressure switch harness with a paperclip to finish up. That will get it running and it'll probably make a little ice until it sucks in the balance of the charge. Also, make sure the Main Fan is running by disconnecting the Fan Switch on the High Line. If you've converted to R134, use only 80% of the R12 charge and aim/stop when the high side reaches 2.5 times the air across the Condensor. When done, reset the Low Pressure threshold to 22.5 psi. Disconnect the Blower Motor with the system on Max and the low side will drop. Note the Low Side Pressure when the compressor cutsout. There's an adjustment screw between the Low Pressure Switch Terminals. Turn it clockwise to raise the threshold; counterclockwise to lower it - about a 1/2 turn at a time - until it's cutting out at 22.5 psi.
