92 A/C compressor won't engage

Max Blast

New member
21
0
1
Buick Ownership
1992 Riv
Hi yall

My 92 HVAC system will not engage the compressor in AUTO mode, in that AUTO mode won't engage on the electronic climate control panel. It lights up for a hot second then clicks into ECON mode. Service AC dash light is on.

The manual troubleshooting steps point to the A/C relay. Per the manual, I've shorted terminals 1 to 4 on the relay and the compressor will engage. The trouble tree says the next step is to replace the A/C relay, which I've done but still no AUTO mode and no compressor engagement. I have a fresh charge of 1.08 kg R12 in the system and it worked until I hooked up my OBD1 code reader, fwiw. ECM code B3334h is set - and OBTW, did you all know you can use the HVAC panel to read and clear OBD1 codes?

Super nifty but I need my AC back.
 

Regal LTD Coupe

Active member
877
180
43
Buick Ownership
1993 Buick Regal Limited coupe 3800 (& 1990 Lincoln LSC SE)
Hi yall

My 92 HVAC system will not engage the compressor in AUTO mode, in that AUTO mode won't engage on the electronic climate control panel. It lights up for a hot second then clicks into ECON mode. Service AC dash light is on.

The manual troubleshooting steps point to the A/C relay. Per the manual, I've shorted terminals 1 to 4 on the relay and the compressor will engage. The trouble tree says the next step is to replace the A/C relay, which I've done but still no AUTO mode and no compressor engagement. I have a fresh charge of 1.08 kg R12 in the system and it worked until I hooked up my OBD1 code reader, fwiw. ECM code B3334h is set - and OBTW, did you all know you can use the HVAC panel to read and clear OBD1 codes?

Super nifty but I need my AC back.
Sounds like typical symptoms of an uncharged system. Have you confirmed it is still charged despite recharging? Have had a complete can discharge from the system in less than a day before. Unplugging a battery terminal for 5 or 10 minutes should clear any codes.
 

HotZ28

Full Member
8,093
766
113
Buick Ownership
1996 Roadmaster Limited Collectors Edition 58k - 1996 PAU
That's what I though too. The low side has held 60 PSI for two days.
60 PSI on the low side is out of whack! What was the ambient temp where you checking it? You should have low side pressure in the 40's or less, if not above 100-deg ambient.
______________________________
 

Max Blast

New member
21
0
1
Buick Ownership
1992 Riv
Sounds like typical symptoms of an uncharged system. Have you confirmed it is still charged despite recharging? Have had a complete can discharge from the system in less than a day before. Unplugging a battery terminal for 5 or 10 minutes should clear any codes.

SOLVED - it was low on refrigerant. 60 PSI is way too high on the low side indeed, but that was the static pressure. The 334 code was preventing the HVAC panel from engaging the compressor so I cycled the battery to clear the code, and then it worked - sucking up two cans of OEM refrigerant and then blowing cold. Now cycles around 40 PSI on the low side.

Thanks for the tips.
 
Get your turbo buick badge right here!
Top