A/c works only hotwired

[ichoplin]

Im helping a buddy with an 06 2500 with a/c problems. His compressor will only turn on if it is jumpered to the battery. We tested the wires at the connection and there is 12volts there, but the comp won't turn on with just the connector plugged in. The pressure switch by the pass side tire is new and it is showing around 40psi on a cheapy gauge.

Could this be a TPIM issue? We're at a loss since we have 12 volts at the compressor connection.

Thanks

Ian

 

[AEdelheit]

Do you have ground at the connector aswell?

 

[JKosten]

40l. bs is very low for system pressure. It should be almost twice that with the system off.

 

[ichoplin]

Yes, the connector has a ground.
It is 40psi with the truck and compressor running.
Thanks
Ian

 

[mweiman]

Watch to see if the clutch will cycle in at all when you first start the truck and turn the a/c on. I just replaced the compressor on an 06 mega cab that must have been drawing too much current. When you first started it the compressor would cycle on I think 3-4 times and kick out after a couple seconds then shut off completely, all within about the first ten seconds. Restart the truck and the same thing again. You could see some metal filings on the clutch also. I am not sure how much amperage it should draw.

Matt

 

[ichoplin]

Thanks Matt, we'll look at that this afternoon.
Ian

 

[JKosten]

Yes, the connector has a ground.

It is 40psi with the truck and compressor running.

Thanks

Ian

That is way for the high side and way high for low side.



What are you using for gauges?



High side should be ~150-250 and low side ~10-25. (Those are rough guesses). You need to look up the specs for the a/c system.

 

[B.G. Smith]

On R-134 system the cut off pressure is about 26# but i don't believe the 06 has a clutch cycling switch. At idle your pressure seem to be right, evaporator temperature is 40deg at 36#. Normal would be 25/43. How did the trouble start? The compressor won't run if the fan is not operating. Check the fan speed resistor under the glove box, it is mounted in the airstream of the AC and is held in place by one small screw. If it is bad the AC wont work, could be bad or just a bad connection as it plugs into a receptacle with several terminals. bg

 

[ichoplin]

Thanks, I'll tell him to check that too.
Ian

 

[ichoplin]

I've passed on all the suggestions to my buddy. I haven't heard back if there's been any change.

Thanks for all the help.

Ian