AC Intermittent Fail

[General Mishap Co]

Greetings
I just acquired my first GMC product(2003 Yukon Denali) and I'm hoping someone here can help with an AC problem I've noticed 3 times now in 2 weeks. AC is cold and consistent while driving, however, 3 different times at cold startup, I've noticed that the AC blows hot while I'm idling in park. Also noticed, while its blowing hot, the compressor is short cycling at about 10 seconds or so. It seems that as soon as I start driving it gets cold. When I then park it, but leave it idle, it stays cold.

The issue seems to be only at cold start and only sometimes.

Also, this may or may not be related, but I've noticed the temp and compass LCD in the rearview mirror intermittently will flash on and off and a regular steady pace. The "passenger airbag" light on the mirror also flashes at the same time.

I'm wondering if these are symptoms of a failing BCM, or individual issues? Any reliable way to test?

Thanks
Sean

 

[Doubeleive]

the digital ac control units are known to go bad if that is what you have, could also be low freon or r34 (whatever is uses)
the mirrors sometimes get loose solder inside and go funky, some people take them apart and re-solder them but a used mirror from the junkyard is cheap also, if you get a used one it has to be the same model mirror.

 

[OR VietVet]

Welcome to the forum from Oregon. Wes is on the track with you. I would also check all the grounds at the engine and frame areas, especially in an area where they use salt on the roads. Several threads here about that. This link may help you.

https://www.fixmyoldride.com/Chevro...e7e5cd24ed24635&at_ab=per-2&at_pos=3&at_tot=4

By the way, the a/c problem sounds like a low system. Attach gauges and post the pressure readings here.


We recommend that you put all your rig(s) info in your signature so we all don’t have to guess at year, make, model, engine size, trans, rear axle locker…….etc. While you may have posted pertinent info in your first post, you may forget to do it again and the info is needed by us anyway. Makes it way easier on all members that attempt to help, to have that info right up front. It is also recommended that you take a pic of your RPO codes, on the inside cover of the glove box, and post that image in your signature. All this info will greatly help those that will try to help with a problem.


If there is any other info, like upgrades, mods or recent mechanical/maintenance work done, that would be helpful in any post as well. Too many times a question is asked by the poster and after about 10 responses we find out that the poster has done recent work to attempt to fix the problem or work that was done that SEEMS not related to the problem.

 

[General Mishap Co]

Thanks for the input. I'll check the pressure and post. I'll also add info to my signature.