Rear A/C Issue

[steven76]

Hey...

When I turn on my rear A/C on, it starts to kick on, I get a puff of air for about 2 seconds, then it shuts right off. Front A/C is fully functional with no problems.

Any ideas?

Thanks

 

[Mooseman]

How about heat? After you get that puff of air, do you still hear the fan blowing? Have you tried the override switch next to the shift lever to force the fan on?

 

[The_Roadie]

If it's the fan that quits after a short time, I'd suspect the speed control module. It's electronic, not a resistor pack like some front blower speed control units. Replacement has been discussed here and on trailvoy.

 

[steven76]

The blower controls for the rear A/C work perfectly at all speeds and directions when the TB is off but the key in the run position.

But, as soon as I turn the TB on, the blower quits after 2-3 seconds. The fan is no longer running when it shuts down.

I guess I should start with replacing the speed control module, but I'm confused about why I would only have the problem when the TB is running.

 

[The_Roadie]

That's a unique problem, and pretty much only the HVAC control module in the console is involved. You could troubleshoot it with a meter or a scope at the speed control module to see if it gets its PWM control signal or not.

 

[Mooseman]

Check the connector on the blower. Had an issue on my Montana's rear blower where it sometimes worked and sometimes not. The connector had melted down. Maybe when you have the engine running and the alternator giving full power, the extra juice is too much for the connector.