sst37chevy

The ac has stopped working in our Tahoe. The dash controls work and act like they should. Have checked it out and it is not getting power to fuse # 17,for the ac clutch. I have jumped it with 12 volts to the right side of the fuse and it will work fine, does want to freeze up when thaws out it will go back to working right, just don't like to jump it like that, afraid might do more damage. I think it is not getting a ground to the relay. I put in a new fuses box in it after ruining the original one by too much force on the fuses checking it out. Now that winter is just around the corner may not need it as much but need to get it to cycle with the defroster. Forgot to mention that this a 2008 Tahoe.
Thanks Dan

a55bruce

The "A/C CMPRSR" relay supplies power to the fuse. The relay is controlled by the Engine Control Module (ECM).
Some ideas as to why the relay is not energizing:
Low Freon (could also explain the freezing-up),
The A/C Low Pressure Switch malfunctioning,
The A/C Refrigerant Pressure Sensor malfunctioning,
Bad ECM,
Corroded connectors or wiring issues.

sst37chevy

I think the freezing up is caused by the ac being jumped to power when I do that, then it doesn't cycle the compressor. Have tried to jump the two switches with no luck on that. I am afraid it might be the ecm, with no one close to reflash a new one if I replace it will it start and run if it is programmed to our vin. Thanks Dan

cleveland63b

so you unplugged the low pressure switch and jumped the connector with no change? Have you tried swapping relays? Do you have a multimeter? I usually start out by getting pressure readings and checking the refrigerant charge but if you don't have access to tools for that its tough to get a baseline.