strange climate control problem

ruswin

Registered User
My 93 has started doing something strange. When idling or running normally the a/c blows normal with the climate control on auto. When I step on it a little bit and put a load on it, the fan idles back to barely blowing at all. I switched the fan control to "max" with the same results. Am I looking at a computer problem, climate control module prob or what?




Come on... sccoa members to the rescue!
 
What do you mean by step on it, or put a load on it. One some of the cars there is a WOT cut off relay that cuts out the A/C compressor clutch when you go wide open. It's possible the climate control throttles back the fan when that happens.

Otherwise I would be thinking that maybe you have a bad ground at the resistor pack or the motor.

Could also be your Alternator is failing. I'd start with getting the alternator checked if you don't think it is the WOT relay.
 
A possible explanation....

I may not get this exactly right, but I recently had my AC worked on by a guy that knows Fords inside and out (retired Ford Service specialist). He said that on my '92, the vents are controlled by a vacuum line, and if you put the engine under load the vacuum to the airflow control will drop off causing the cold air to be redirected through the defrost vents. He said there is a regulator valve that can be installed to prevent this. I really wasn't catching all the details, I was just happy to get some cool air before the hot summer days down here in Atlanta...... May be worth a little research, though.
 
It doesn't have to be WOT, just moderately loaded. I'm not seeing any other electrical problems so I'm not to sure about it being a alternator prob. As far as vacuum "pressure", isn't the climate control "brain" more complex than that for fan speed.
Since it is variable depending on the conditions, I would think something electronic is going on.
 
I agree, it's most probably a vacuum motor problem. When you accelerate, the vacuum drops on the car and the motors that control the vents (air flow) tend to think that you have redirected the flow somewhere else rather than where you wish.....they end up trying to make air flow thru everywhere at once, hence low air flow....I believe there is a fix that can be installed to eliviate the problem. Check with FORD for a TCB....


Good luck....95SC
 
Sounds like a problem I had with my 93 SC. Turned out to be the red colored hard plastic vaccume line. This line connects to the bottom of the vaccume tree located on the firewall, drivers side.
 
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