JimRockford

Hi everyone,

I'm new to the forum, but glad to have found this place. I have a 2005 Tahoe Z71 that I've owned since new, and have worked very hard to keep it in like new condition.

Right now I have a challenge that I've sent it to the dealership for numerous times, and it never comes back fixed. The rear A/C works fine, but when on heat, it does not blow when set to Auto. If I set the heat level and blower speed it works fine, but if I set it to Auto and set the desired temperature, there may be a very, very slight flow of air come out, but not enough to really detect. As I recall, if I set the temperature to max, where it "clicks" up high I think it blows then, but will not when set to a temperature mark.

The dealership keeps telling me they have called Tech, and they say when set to Auto it determines how hard to blow and it's all working correctly. Well, I've been driving this truck since 05, and no it's not.

I haven't dismantled anything yet, but I'm pretty good with a Fluke meter. Any insight would be very much appreciated.

Thanks in advance.

oilcanhenry

Not familiar with *dual* auto HVAC systems, but since the heat works on manual mode, that makes something like a sensor, a relay or a switch is likely not operating properly, the likely culprit, IMHO. At least it works on manual mode, for now.

When I was a young lad, I don't think even Cadillac's came with such a system, and lots American cars and pickups did not have air-conditioning as standard equipment, like is pretty much a standard, non-optional, system nowadays, with A/C even on semi-trucks, thankfully.

JimRockford

Hi Henry, and thank you for the reply.

I'm assuming that since it blows A/C in the summer, which is 10 months of the year here *ughhh* the doors have the ability to open and close in Auto. Therefore your thoughts of a sensor make sense in my mind. My issue is that I have no idea where the doors, sensors, servos, etc. are even located to start troubleshooting. Maybe I should Youtube that. Put me on a residential or commercial HVAC unit, give me my meter and I'm good. Just a little lost on what to open here.

Thanks again.

Cusser

Then demand a refund; if dealer doesn't comply, then contact GM district representative, or dispute the charges with your credit card company. There's an implied warranty
/unjust enrichment statute in every state, like when you pay for a repair, you must receive the repair, not a guess. We don't pay for guessing.

Years ago I got a refund when a dealership could not fix our intermittent non-closing sunroof on our 2005 Yukon, they actually said "we have no idea what's wrong", and I had to fight them but did get a full refund. That sunroof ALWAYS opened, but when wouldn't close, not a sound or whirr. Dealership at first thought faulty switch, but in reality sitting for a day sometimes worked. First return visit to dealership was 24 hours after that first repair. Of course dealership had $50 hazardous waste fee on my bill, but I had asked for all parts back, and it turned out that NOTHING was disposed of, so that charge came off first day.

End result: I took out the sunroof fuse, at least now it cannot be stuck open !!!

oilcanhenry

Not a problem, Jim. I wish now I had gone into HVAC home or industrial HVAC myself, not driving a truck. Used to pay well, but not anymore. Oh well, I'll be retiring soon!