1990 Dodge Dakota LE, 3.9, 2WD

I'm not sure if I'm calling it the right thing. I'm talking about the dash module that regulates the air flow - panel, defrost, foot, fan speed, etc...

Anyway, my air flow is only to the feet and defrost no matter what I push on the panel.

Can anyone advise me on what the fix may be?

 

First thing is to check your vacuum feed into the cabin; that's by vacuum, and if that hose has snapped, no vacuum == stays on heat and defrost.

Also, it's called the "HVAC Control Module". Usually just called "heater control".

RwP

 

Thanks Ralph.

The heat isn't on. I feel the AC blowing. It's just blowing only on my legs and windshield.

Could that still be a vacuum problem?

 

The vacuum doesn't control the compressor; instead, it controls the divertors, and the fail-safe mode is defrost/floor.

Some examination of the Factory Service Manual ( section 24 most likely for 1990; it is for 1988 anyway! ) will show why, and where that vacuum line is. But to help - it goes in where the heater hoses go in, and on my 1988 it's off the 3-way at the power brake booster (that 3-way has one way to the engine, one way to the cruise control servo, and one to the cabin for the HVAC controls)

RwP

 

Found the problem. Thanks for your advice Ralph.

Turns out the mechanic that had been troubleshooting a different problem for me put the check valve on backwards.

Once I turned it around, all was well again.