04 Sub A/c

Rockpicker · July 29, 2011

My daughters 04 seems to have the A/C and heater at odds in the front. The rear air works fine but the front seems as though the heat is on with the A/C. Was told it may be a valve under the dash. I am assuming that the door that should close the heater core off is not doing its job. Has anybody run into this kind of situation, and what was found to be the culprit?

Thanks, Jim

tesnoboy · July 29, 2011

My daughters 04 seems to have the A/C and heater at odds in the front. The rear air works fine but the front seems as though the heat is on with the A/C. Was told it may be a valve under the dash. I am assuming that the door that should close the heater core off is not doing its job. Has anybody run into this kind of situation, and what was found to be the culprit?

Thanks, Jim

Sounds like the blend door actuator is bad.

wages999 · July 29, 2011

I just got a letter from GM about extending the warranty on the heating system in my '04. You might want to check with a dealer to see if yours is covered.

Rockpicker · July 29, 2011

Was just looking at parts diagram and it looks like it requires two actuators one top and one bottom. Both same part #. Is it likely that both are bad, or will one just not move the door by itself?

Have the glove box out and the bottom cover off. The bottom one is no problem but the top one may be a bitch.

Will pull the bottom one off and see if it functions. With any luck they are not both bad and the bad one is the lower.

However if Murphy's Law comes into play..........profanity may ensue.

Rockpicker · August 1, 2011

So after checking out the blend door motor idea Fri. night, decided that was not the issue.

Pressures were ok and rear air blows very cold. Have a cold and sweating inlet pipe to front evaporator but lukewarm coming out of evaporator to accumulator.

Decided may be restriction in evaporator. This morning flushed evaporator, replaced accumulator and orifice tube, vacuum and recharge. Works exactly as before. Bummer!

Question now is, with the rear air system, is there any proportioning valve in this system that divides flow between front and rear.

I cant figure why I cant get a cold pipe on the outlet of my front evaporator. Seems as everything is circulating to the rear system and very little to the front.

Thanks for any ideas or suggestions, Jim