I have a 1986 Chevy four door dually 454 with factory A/C. But the A/C does not work. the fan does work but the compressor clutch never accuates. Where do I start? I have checked the fuses...
CK5
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How to diagnose A/C not working?
- Thread starter eagle mark
- Start date
k20
3/4 ton status
is the clutch getting 12v to actuate?
Slapperbar
Retired Navy NDT Examiner
Check freon pressure, too low, it won't run.
British Slave
1/2 ton status
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With the engine running and the AC turned on. On the passenger side, there is a switch mounted to the dryer. Unplug it and put a jumper between the two wires and see if the clutch kicks in. If it does, you are either low on freon or the low pressure switch is bad. Here you need a set of gauges to check pressures. If you hook a gauge in the low side, and jumper the low pressure switch and the pressure pulls down below 20 PSIG, you are low on freon. If the pressure stays arond 25 to 40 with the engine idling, the switch is probably bad. The switch simply unscrews and screw a new one in.
I jumped the switch as you indecated and the clutch engaged, but after about five minutes still no cold air. So I guess I'm low on freon. Don't have any gauges and never took a class on A/C. So do you know where to start?
I saw an article on a r-12 equivelent that was supposed to be way better than r-134 and no need for changes to existing equiptment...
British Slave
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I haven't used the new stuff yet, but you will need to fix the leak first. Look for oily stains around the AC components. look at the underside of the hood, if the compressor is leaking it usually shows up there right above the compressor. If the compressor seal is leaking, I have found it best to replace the whole compressor, clutch and all. I just have never had luck in changing the seals, and there are a couple of special tools for pulling and installing the clutch.
It takes some special tools, such as the gauges, a vacuum pump, etc. Might be better off to find some help or let a shop do it.
I converted a Ford truck to 134-A and had no issues with it. But you have to completely evacuate the system, change the oil out, and best to install a new dryer/receiver.
It takes some special tools, such as the gauges, a vacuum pump, etc. Might be better off to find some help or let a shop do it.
I converted a Ford truck to 134-A and had no issues with it. But you have to completely evacuate the system, change the oil out, and best to install a new dryer/receiver.
kd7kmp
Registered Member
DON'T USE R-12 SUBSTITUTES!!! They are no good and don't cool very well. No shop will ever work on your A/C if you fill it with an R-12 substitute. If you are indeed low on refrigerant then you need to determine if there is a leak. Some oil seepage and refrigerant loss is normal over time. It wouldn't surprise me if your truck has lost enough R-12 through normal losses that you simply need to recharge it.
Kevin
Kevin
