Help: Ac cold/hot in 10 seconds

[firebirdtoddd]

I HAVE A 2006 2500 HD WHEN TRUCK FIRST STARTS AC IS BLOWING COLD AIR THEN AFTER ABOUT 10 SECONDS OF RUNNING AC STARTS BLOWING SUPER HOT AIR /IF U SHUT OFF TRUCK AND RESTART DOES SAME THING ANY INFO ON THIS PROBLEM WILL BE A HUGE HELP THANKS

 

[LBZ]

A/C is tough to diagnose without the right equipment. Could be a hi or low pressure switch, could be the clutch on the A/C compressor, might just need a recharge.
Best bet is to take it to a shop that services A/C IMO.

 

[JDub]

The Blower Motor Resistor is very prone to failure in the GM trucks as well, in fact I believe GM had an extended warranty type recall on them. That would be my guess if it blows cold for a while.

 

[DAVe3283]

What about the blend doors? They have been known to glitch out and do what you are describing. Check to see if the A/C compressor is still cycling while it is blowing hot.

Sent from my Galaxy Nexus using Tapatalk 2

 

[jc1843]

It is most likely the blend door-- common problem. If it is the one on the bottom of the AC/Heater housing, it is fairly easy to change. You can try this-- turn the ac controls to off, remove both the negative cables-- wait about 10 minutes-- install the cables, start the engine-- DO NOT TOUCH THE AC CONTROLS FOR 5 MINUTES. That should reset the AC to default.

If it was the AC system having a problem, it would never get very cold.

The resistor only controls the fan speed. Common problem when you do not have all speeds.

 

[firebirdtoddd]

thanks every1 for ur help/ i talked with my friend at gm and tryed what he told me to do -after the battreies are disconnected on these trucks u need to pull the ac/hvac fuse to reset them apparently /tryed this this morning and all is well so far Thankls again for all ur help :thumb::thumb:

 

[seth999]

Make sure the compressor is kickin on and staying on...if it is you have one of the issues above...also you could have air in the lines or too much pressure on the high side...AC is hard to diagnose without seeing it