I repaired a leak in the AC system, evac and charged, tested, everything worked good including engine fan cycling, compressor cycling, pressures good, cooled good. Customer took truck, said it worked 45 minutes and quit. I checked compressor and determined clutch had grounded out and I have bench tested it to verify. Replaced compressor, accumulator, and orifice. What I have now is good power to the compressor, controlled by push button switch on dash, but it still won't engage the clutch. There is a second wire off compressor which would be the ground circuit, It goes directly or indirectly to the fan solenoid on the firewall. There is a second wire off this solenoid gray in color, can't read a number, I don't know where it goes. A wiring diagram would be of tremendous help but the several I have found only show a single wire to compressor coming off the 2 pressure switches on the firewall and not the same circuitry. I need an accurate wiring diagram and the location of the compressor relay I'm not sure it has one, but most info I have rec'd indicates it does along with any advice you might offer. Something that is odd is the power to the two pressure switches along the firewall is a dim light. The power to the compressor is good, bright light. I have never got power to the pressure switch at the switch located near the left top of radiator. Thank you
This may sound crazy but I have had issues with vehicles in the past and I have had to spend the day at the junk yard and have found answers to wiring problems. There are so many sources for diagrams and it seems none are of any help. so the junk yard has provided hands on resolutions and you can visually follow what goes where. Just a suggestion that has worked for me several times.
SOURCE: 1991 Sierra GMC AC control problem
The follwing is a cut and paste from a service bulletin:
Bulletin No.: 461202
Date: May, 1994
SUBJECT:
A/C CONTROL HEAD FLASHES OR ERRATIC OPERATION OF A/C CONTROLS (POLISH
TERMINALS)
MODELS:
1988-94 CHEVROLET AND GMC TRUCK C/K MODELS
1990-94 CHEVROLET AND GMC TRUCK TOPKICK/KODIAK MODELS WITH C60 OR C69 AIR
CONDITIONING
CONDITION:
A/C Control Head flashes, performs erratically or malfunctions.
CAUSE:
Light surface corrosion on the Control Head terminals.
CORRECTION:
Remove the A/C Control Head and while holding the unit with the terminal
cavity down (toward the floor) so no particles will fall inside on the
circuit boards, polish the terminals on both sides of the cavity with a lead
pencil pink eraser. Do not use an ink eraser or other abrasive such as a
small wire brush or sandpaper, etc. Doing so will remove the terminal
coating and degrade the contact surface.
Performing this procedure, in many cases, will make replacing the Control
Head unnecessary. Using this procedure in conjunction with the A/C circuit
diagnosis found in the Electrical Diagnosis Manual and especially before
replacing a Control Head for any reason is recommended.
After polishing the Control Head terminals, but before reconnecting, check
for proper terminal contact as described in the applicable electrical
diagnosis manual. If contact is good, apply dielectric grease (P/N 12345579)
to the harness connector terminals. Please do not apply grease to the
Control Head.
SOURCE: I cannot locate my low pressure switch on 1995 Corsica.
First of all, from the discharge port of compressor to the condenser(the device in front of the radiator) from the condenser to the metering device is all the high side or high pressure. From the metering device through the evaporator including accessories back to intake of compressor is the low side or low pressure.It is important to know that entrained in the refrigerant is oil for lubrication. The combination of pressure and oil could be a safety and environmental hazzard. I know on older GM models one could short out low pressure switch by jumping the low pressure switch with appropriate gage wire. This would temporarily permit one to add aditional refrigerant to system.The job of the low pressure switch is to protect the compressor from burning up due to lack of refrigerant by shutting the system down.. Now, if the refrigerant is low it had to escape, meaning a leak.(refirerants don't just wear out)Refrigerants are notorious to being determental to the environment. Older refrigerants contained hydrocarbons that destroyed or reduced the ozone levels to reduce this from happening strict laws of handling and recovering a/c refrigerants were enacted & exhorbitant costs were placed on the offending refrigerants.In order to save some some money some untrained or knowledgeable people are continuing attempting to repair their systems risking injury like permanent eye injury.Is it worth it? No one (I believe ) intentionally desires to be hurt.However, by attempting to do something that you haven't been trained on can make you more susceptable to injury or accident. An in a instan one could trade off perfect vision to partial or even total blindness.This is not to just to scare you but gives you an opportunity to weigh all the decisions prior to attempting something one might be unfamiliar with.Most of the accidents I've witnessed at home and work were individuals taking short cuts,hurrying or attempting something unfamiliar with.Not all accidents fall into this category but be aware rehab is no fun and often not totally complete. Lets not compromise your safety and the well being of our environment.
SOURCE: 1992 gmc c1500 ac compressor relay location
I pulled this from another web site
"The AC clutch relay is located inside the cab on a metal bracket that is easiest to see when you remove the glove box compartment.
The relay is on a metal bracket bolted to the top of the plastic air box, forward and to the center of the dash from glove box.
There are three relays in a row on that bracket. The AC clutch relay is the end one closest to the driver’s side."
Testimonial: "Right on target... THANKS"
SOURCE: 1997 Linclon car No power to A/C clutch.
take the pressure switch connector off and jump connector- if clutch engauges you either have bad low pressure switch or are low on freon.
SOURCE: 1989 ciera orange wire going
You didn't post an engine size but you are correct in thinking there is a fusible link that blew when you grounded the orange wire but there is also an inline fuse that protects the oil pressure switch and the fuel pump relay. It is usually located on the firewall.
You can check the fusible links near the starter for continuity. If one of them is burnt up start there by replacing it. If none of them are bad you will need to find the inline fuse. At least the 3.3 liter engine is set up this way.
I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa
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