Air Conditioning still not working

[72Blazerod]

Hi Guys,

I was referred to an HVAC thread on this site and asked some questions on that thread, but received no reply. (My truck is a 2006 GMC 2500 Crew Cab with dual zone A/C). My driver's side A/C runs cold for a while then it blows out warm air. It works properly if I shut the truck off and turn it back on. The other thread said that this problem was linked to an error code coming from the HVAC. What I want to know is can I clear this code with a plain-jane (read "cheap") OBDII reader? I haven't used an OBDII reader before so any tips would be handy. Anybody know the code number?

Thanks,

Rod

[DmaxMaverick]

I don't think so, generally. I don't know of any low-end readers that will clear any but the "P" codes (engine/emissions). The HVAC should be a "B" (body control module) or "U" code. I haven't seen/used all readers, but enough to suspect they are very low function, and essentially restricted to emission related DTC's. The higher-end readers/scanners can clear some/most of them (like the Actron 9145+, at $200+). You can also do this with the PC based scanners.

In most cases, I have found, a 30 minute battery disconnect (both) and grounding of the batt+ cable (to engine or chassis) resets most codes. Make sure both batt+ terminals are disconnected before grounding!! Sometimes this doesn't work, but I don't know why (maybe it needs a longer time period). Just disconnecting the power (without grounding) can take several days/weeks to produce the same result.

[Heartbeat Hauler]

Just go to any Advanced Auto/Auto Zone, they will read up and clear any codes you have free of charge.

My AC would work fine around town, but when I would head out on a trip it would stop working. This was also happening when it was really hot and I drove a lot. It would just start blowing warm air. If I shut it off for awhile maybe an hour or so, it would start working ok. Turned out it was one of my switches Low or High pressure...I can't remember which one it was. After replacing the switch my AC works great now with no issues.