DeputyPelican
Newbie
I'll preface this by stating I've got a 1997 Sierra with a fairly new (replaced approx. 2 years ago) a/c compressor, and I just checked the A/C refrigerant today and it was still within proper range.
For the past three-to-four weeks my A/C has been blowing properly until I reach highway speeds, then it begins to blow lukewarm air. One of the times it began to do this I turned the A/C circulation button off and it seemed to fix the issue temporarily; Now that doesn't even fix the issue. When I first start the truck it blows cold, and it seems to only start having issues after driving for a few minutes. I did replace the A/C module (HVAC control module) a few weeks before the issue began. The module I replaced is a cheap Dorman branded one from amazon. I had to replace the module because the OEM one had the common issue of only blowing at the highest or next-to-highest setting.
What do you guys think... expansion valve or would it be the module? Also, I don't think it's relevant but worth mentioning I'm fairly certain the heater core is beginning to fail due to the gurgling sounds coming from the glovebox area, and the truck unexplainably overheating a few months back after a short road trip.
Thanks for your time.
For the past three-to-four weeks my A/C has been blowing properly until I reach highway speeds, then it begins to blow lukewarm air. One of the times it began to do this I turned the A/C circulation button off and it seemed to fix the issue temporarily; Now that doesn't even fix the issue. When I first start the truck it blows cold, and it seems to only start having issues after driving for a few minutes. I did replace the A/C module (HVAC control module) a few weeks before the issue began. The module I replaced is a cheap Dorman branded one from amazon. I had to replace the module because the OEM one had the common issue of only blowing at the highest or next-to-highest setting.
What do you guys think... expansion valve or would it be the module? Also, I don't think it's relevant but worth mentioning I'm fairly certain the heater core is beginning to fail due to the gurgling sounds coming from the glovebox area, and the truck unexplainably overheating a few months back after a short road trip.
Thanks for your time.
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