Basically just one line and the two stubs going through the firewall to evap core need flushed. I just ordered a flush gun so I'm gonna do it myself now. George Costanza - good, flush those two lines then. Is there a risk with starting out with 9 oz in the comp? Yes, do not engage the compressor wi...

I'm wondering why you feel more needs to be flushed, with all those brand-new components.

Hopefully you confirmed that 3 oz. of oil in the compressor and didn't take that on trust. If so, add 6 more oz.; if it's all buttoned up already, then lot the shop add the remaining oil and do the rest.

I've had to replace an electronic actuator for the blending doors on two GMC vehicles, both stuck in the "hot" position.

Thanks Cusser.I had it into kwikfit recently who evacuated the system then said they couldn't regas it as it had a leak.I bought an STP EzChill and it was going well and was in the green zone when suddenly the pressure went to zero however a few minutes later it went back suddenly but would not sta...

First guess would be that low refrigerant level is getting the pressure switch to do its protection job, and thus preventing the circuit to the compressor clutch from "closing"/completing. So the center part of the AC compressor doesn't engage or turn. Have a shop look at this, they can ac...

Toddmann wrote:Fixed it. Thanks for response.

Todd - you're supposed to post what was wrong, and what fixed your truck, to help others here !!! We all keep learning.

A/C clutch will not engage. I can jump with a paper clip at A/C clutch relay and clutch engages and A/C blows cold air. You are likely low on refrigerant or your pressure switch is bad. Do not simply jumper the switch and run the unit, except for the test that you did, can damage the system because...

Compressor "off" pressures do not tell much. I see where with compressor engaged, and at high engine rpm, that your highest pressure is 200 psi. I'm in hot Arizona, and all my R134a vehicles typically measure 250-275 psi on the high side. Feel your lines going into and leaving the firewall...

When parked in the sun, remember that seats, dashboard, interior can be alike 140F or more, takes like 15 minutes until the cooling really sets in. Start out with outside air (vent) in because that hot air is COOLER than the interior's air; later switch to recirculate mode.

You were over 100 grams R134a low when it was re-filled. I wonder if you have leaked refrigerant since then.

Also make sure all your cooling fans are operational.