[caddy123]

Replaced ac compressor in 2015 along with new drier, orifice tube, and temp sensor. Added dye for future issues. Had no issues recharging system at the time.

I just got the ”low refrigerant a/c off” notice. Found leak at low pressure switch. (pag oil and dye all over it) Replaced with new ACDelco OEM switch and replaced shrader valve.

Check everywhere else with UV light for leaks. Found no evidence of leaks at compressor, lines, or fittings. Pulled vacuum. Trying to recharge. Compressor won’t engage. Clutch moves freely. Swapped AC relay, clutch still won’t engage. Jumped relay (pins 30/87), clutch engages and spins but system will not take charge.

If I can get the clutch to engage by jumping, what is preventing system from drawing in refrigerant? What am I missing? Thanks.

 

[sefiro]

Controller will engage clutch if j
- pressures are good
- engine temp ok
- air temp requires

During replacement of the lower switch, you might have installed a faulty one.

Confirm pressure with a guage.
Check fam to determine if switches are normally open or closed and bypass accordingly.
(Ie I believe the low pressure switch is normally open and closes when enough pressure is found. So you could pull the pigtail and jumper the two wires to accumulate the closed state of the switch)

 

[basscatt]

Replaced ac compressor in 2015 along with new drier, orifice tube, and temp sensor. Added dye for future issues. Had no issues recharging system at the time.

I just got the ”low refrigerant a/c off” notice. Found leak at low pressure switch. (pag oil and dye all over it) Replaced with new ACDelco OEM switch and replaced shrader valve.

Check everywhere else with UV light for leaks. Found no evidence of leaks at compressor, lines, or fittings. Pulled vacuum. Trying to recharge. Compressor won’t engage. Clutch moves freely. Swapped AC relay, clutch still won’t engage. Jumped relay (pins 30/87), clutch engages and spins but system will not take charge.

If I can get the clutch to engage by jumping, what is preventing system from drawing in refrigerant? What am I missing? Thanks.

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you should update your profile to include the year and model of your Cadillac -

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FIRST - you MUST clear the codes -
ANY AC related codes will disable the compressor -

can we assume you have a real set of gauges connected to BOTH the high side and low side ports?

 

[caddy123]

FIXED! Yes, I had cleared codes - forgot to mention that. Turns out there was system issue at all. I had the hoses overtightened on the cheapo Harbor Freight gauges (that I've used several times without issue), and that was stopping flow of refrigerant. Would never have known except I found someone else had the same problem with these gauges. Reset all connections and system took full charge. Nice cold air and compressor cycles normally. Whew! Thank to all for your replies. Much appreciated.