A/C problem

[ljackson]

Hi, I have a 99 Yukon with a 5.7. The A/C is not working. The clutch will engage and turn the compressor if I run a jumper wire to the front plug. It does get cool. I read about a sensor that may not let the clutch engage due to low freon, hi or low pressure. I am not sure where the sensor is. While I had it jumped, I added a small amount of freon. The gauge was pegged when I first started. Now it is reading about 50 psi. When I reconnected the plug, the clutch does not engage. I did not find anything after searching with my exact problem. Is there a sensor that may have gone bad? Where is it? Can I replace it?
Thanks for your help

[truckdude239]

wooooo 50 psi on the low side is way too high should be around 35 psi on low side and 225-275 on high side at around 90 out side. the sensor is normally on the reviver drier

[ljackson]

Thanks for the reply.

I took it to Firestone yesterday afternoon. They told me the compressor is going out. By the way, it was working again when I drove it home and still this AM on the way to work. They want $900.00 to fix it. Can't do that. If the compressor is the case, I will replace it myself. I can get a new comp and clutch with 1 yr warranty for $220.00. I plan to replace the compressor and drier. Should I replace the sensor on the drier? It was listed on Firestone's estimate.

[truckdude239]

compressor , drier and office tube, for warranty

[PT'S 70 CST]

Do not go the cheap route. I made the mistake of putting on an Advance auto compressor and replaced it twice. After the second time I wound up putting an AC Delco one on and have not looked back in two years.


PT

[Ghastlyone]

I learned my lesson years ago about replacement parts.

It's either AC Delco or nothing.

The only thing I buy from Autozone is oil, and air freshners.

[clinebarger]

Originally Posted by ljackson

Hi, I have a 99 Yukon with a 5.7. The A/C is not working. The clutch will engage and turn the compressor if I run a jumper wire to the front plug. It does get cool. I read about a sensor that may not let the clutch engage due to low freon, hi or low pressure. I am not sure where the sensor is. While I had it jumped, I added a small amount of freon. The gauge was pegged when I first started. Now it is reading about 50 psi. When I reconnected the plug, the clutch does not engage. I did not find anything after searching with my exact problem. Is there a sensor that may have gone bad? Where is it? Can I replace it?
Thanks for your help

When you say front plug you mean the compressor clutch coil plug on the compressor? When you jumped battery power to the clutch it got cool but not cold? You added freon then it got warm? To much freon can cause high low side readings. Never just add freon, It takes a certain amount (2.0 pounds if you dont have rear air) Putting liquid freon (cheap can tap charging tool) directly in the compressor is also a very bad idea. Try unpluging the low pressure switch and jumping it directly, see what happens. As truckdude said its on the receiver dryer




[/QUOTE]I took it to Firestone yesterday afternoon. They told me the compressor is going out. By the way, it was working again when I drove it home and still this AM on the way to work. They want $900.00 to fix it. Can't do that. If the compressor is the case, I will replace it myself. I can get a new comp and clutch with 1 yr warranty for $220.00. I plan to replace the compressor and drier. Should I replace the sensor on the drier? It was listed on Firestone's estimate.[/QUOTE]

Firestone can hardly fix a flat. Dont let inexperienced techs/greedy managers sell you somthing you dont need. Get the compressor enable curcuit working first (control head, low pressure switch, bad ground, A/C clutch relay, broken wire, etc). Charge it with the right amount of freon. What was the exact reason they gave for the compressor being bad or "going out"

[bwood]

Originally Posted by clinebarger

Firestone can hardly fix a flat.