2005 SLE AC Issue

jrwsound

2005 Pontiac Bonneville SLE with Auto Climate Control Module

Symptoms: Occasionally the blower does not kick on. One time I powered the AC off and back on which fixed it. Other times nothing will fix it. Just one time the system wouldn't push cold air like the Freon was low. Now that everything is working right, it is in the shop (GM dealer) where they won't be able to do anything.

1. Who is right? My regular mechanic (used to work at a Ford garage) said it needed to be hooked up to the computer to see if the system detects any codes that might point to the problem. Dude at the GM garage doesn't want to do that because he says the AC system isn't connected to the computer system.

2. (Assuming my regular mechanic is right) Until the AC system reproduces the symptoms, the computer won't throw codes anyway, right? So running computer diagnostics will only cost money for no results?

3. Anyone have an idea what might be the cause of this issue?

Thanks!

imidazol97

The motor has brushes which lose contact with the commutator. Above the passenger's left toe next to the hump, there is a round 8 inch diameter circle on the bottom of the HVAC box. That's the motor. With the key ON when the blower does not run, tap that with the toe of your foot. If the vibration makes contact on the brushes and the motor starts you 90% have diagnosed your problem. Replace blower motor from Rockauto.com, Autozone, etc.

The other 10% may be the connector at the resistor pack or blower control module for the automatic temp control model. Poor contact or corrosion causes heat adn teh plastic melts leading to further poor contact.

The AC is not part of the diagnostic on most scanners.

jrwsound

Excellent! Thank you!

imidazol97

When my 03 had a problem, I tapped for a while to keep it running and then it wouldn't work. I got an Autozone replacement because they stocked it. The other box stores did NOT stock the blower motor which works in the Bonnevilles and leSabres for 2003-2005 and others. $139 and I put it in myself. I was careful to check the electrical connector for problems.

I disassembled the motor later and found one of the carbon brushes was sticking in the channel. That explained the burning smell occasionally with the spark jumping the gap as the motor turned. Vibration would let the carbon move closer after wearing or let the commutator move to touch the brush.