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View Full Version : AC blows warm when I hit my brakes


bartman547
Oct 3, 2012, 11:09 AM
I have a 2001 dodge ram, 5.9L, 2WD, auto trans with A/C basic control panel.
When I am driving with AC on normal to dash panel vents it is cold just fine.
When I put on my brakes, I hear a labored hum or change of sound in the dash and warm/hot air comes out of AC panel vents. After releasing brakes and driving a bit, it cools down back to normal cold.
I know the brakes and AC ducting system are all controlled by vacuum, so what is going on?
I have replaced all the dry-rotted vacuum lines and connectors in my vac system and it still does this.
Thank you to anyone who can point me in the right direction.

TxGreaseMonkey
Oct 3, 2012, 11:44 AM
Compressor Test. A bad compressor will normally show the inability to generate enough suction and pressure at idle speeds. If the engine speed needs to be increased substantially to bring pressures in range, it's a sign the compressor is weak. The typical complaint is, "It only cools when the engine is revved or when driving down the road." It's often simple. If we hook, for example, the gauges up and see 80 psi on the low and high sides and the compressor hub is spinning, the compressor is shot. It's not producing suction or pressure. We could add more refrigerant and nothing would change. Compressors must be able to pull a vacuum and create pressure. Compressors last, on average, 100,000 miles.