AC Issues

[69Bronco]

2003 Silverado 1500HD AC started working on and off, pressure in the green. Only 25MVolts at the compressor. Checked all three pig tails, all in good shape. Need help trouble shooting, I believe the AC compressor is not being told to turn on.

[anumber1]

Check the low pressure switch for continuity. Switch should be closed if the system has suficent pressure.

 

If it is open, suspect a defective low-pressure switch.

 

That is if the static system pressure is truly where it needs to be.

 

You could jump the switch to force the compressor to run. This will allow you to verify compressor function. Perhaps get a real gauge manifold on it and look at the high and low side pressure.

 

If you are using some kind of cheap low side recharge kit gauge, suspect the gauge before a bad low side switch.

 

Finally, the fuse is good, right?

[69Bronco]

Thank you for the help. This weekend I used a paper clip to jump the low pressure switch and I also checked the fuse no luck with the compressor. The high pressure switch has three wire plug so I am a bit unsure how to jump the switch. I will check the low pressure switch which should be closed if the switch is good assuming the pressure is good.

[Dnt]

You really need to buy a set of manifold gauges if you wish to diagnose. I do not feel comfortable jumpering anything on these new vehicles as one wrong move and you can screw up several very expensive electronic parts. Most likely you just need a recharge of refrigerant and you are good to go but I would invest in a decent manifold gauge set.

 

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