a/c not very cold!!

'97 k1500 ext cab just had a/c charged, 30-35 on low side 200-215 on high side, air is about 70 degrees @ vents, seems like it should be cooler. System just doesn't cool the cab at all. any ideas? I've checked the recirculation door and it is working. any help would be great.

Thanks,
Jaz

Your pressures sound about right. The temp.at the evaporater should be about 35 f. Check the blend door (temperature actuator) in the duct. Check for 12 volts at the conector.

Blend door seems to be functioning, it is moving from hot to cold and the temp reflects this. Is the only diff between max and cold setting the recirculation door? three wires @ the unit one ground(black),2 volts(blue), 12 volts(brown). Outside air temp hear is 82 degrees and my cab air is 80 with a/c running for about 15 min.:frown:

Thanks
Jaz

It is getting the right voltage but is the blend air door working. The blend air door allows full heat or full A/C or a mix of both. It sounds like your door is not closing on the heater allowing hot air into the duct. I have seen the actuator not working or even a pen stuck in the door to keep it open.

My 1990 Sierra had a similar problem. It turned out that the gasket between the cowl and the airbox inside the truck had deteriorated, so air from outside was coming into the cab. In winter, it was most noticeable cause even with the heater on, the passenger side had cold air coming in.

removed the motor and manually worked the door seemed to be moving too max both directions. checked the motor also and the door was moving as much as the motor. no gears stripped within the case. also had the pressures rechecked low side @ 33, high @ about 220, ambient temp about 94 degrees.

dont know alot about a/c but when i helped a buddy fix his it was the orfice tube (this acts like an inline filter) was stopped up and his did the same thing but to change it you have to evacuate the system then vacumm when you charge it back up...but before we get that far does the compressor seem to be cycling like it should ?? it should stay on more than off in hot weather

yes seems to be cycling just fine everything seems to bee working, just air is not that cold and definately not cooling the cabin!

Is the air flow through the vents good ie. nonrestristed the the coil could be dirty resticting air flow through it thus not cooling enough though the pressures would be a little higher , I'd try cleaning inside and out side coils and see it that works.

I'll give it a try! Anybody think it would be a bad idea to use compressed air or shop vac exuast back feed thru floor vent with recirc door open to cab? really dont want to tear out the whole unit if possible.:wink:

Your readings on the gauge are good. If you had a stopped up orifice tube they would not be. Quick check, after compressor runs for 10 min, is the large (suction) line sweating while the small (pressure) line is hot to the touch?
They way I have my unit charged, large line sweats all the way back to the compressor. I get 37-40 degree air out on MAX with blower next to HIGH position, 90+ degrees air temp, 50-60% humidity.

It is cold to the touch but does not sweat! and the other is very warm to touch.

Put a thermometer on the cold pipe. it should be about 35 f. Hot and cold are relitive without a thermometer.

pipe temp @ 59-62 degrees. What kind of high pressure can the system take. I don't what to start blowing seals and have other problems.

Sounds like you are low on R134A. High side can go over 300# and still ok. Have the system presure and temperature check again. you might have a leak.

removed the motor and manually worked the door seemed to be moving too max both directions. checked the motor also and the door was moving as much as the motor. no gears stripped within the case. also had the pressures rechecked low side @ 33, high @ about 220, ambient temp about 94 degrees.


Is this with the engine running? What are the static pressures? If you had a shop charge it for you then take it back and let them deal with it. Static pressure on low side should be 100+ psi when it is 94 outside. If not then you are low on refridgerant.

these are engine running pressures. No shop , buddy has a set of guages and some r-134a. He's a HVAC guy, but doesn't do a lot with automotive. Guess I'm headed to the shop!:shakehead