HELP! Climate Control Fan - Troubles

Crunchee

Registered User
1993 SC - 5 Speed

Hey. The ventilation fan motor blows full speed all the time when the key is on regardless of what position the control switch is on.

It even blows when switched to the off position. Changes to mode, temperature, AC vs not..make no difference either. She just blows and blows.

I checked the fuses under the dash, and in the main power box in the engine compartment. All good thanks.

Normally I would think that the switch / speed control is shot...since current is flowing even when switched to off position. But don't want to assume that....yet.

Anyone have experience with this?

Thanks
 
Thanks for the information. Do you think there is current flowing to the resistor pack when the fan motor speed is OFF?

And same question for when the mode button is OFF also?

Getting that wind in the face affect all the time these days :)
 
I wouldn't have thought so, but as you can see in the thread I linked to, the user described the same problem as you, and the pack solved it for him.

My thought is that it is a failure mode that has occured. The motor is turned on by establishing a ground. I.E. it is always hot, it is the ground that completes the circuit. So if the resistor pack has failed to ground, that would energize the fan, regardless of the switch setting.

Using ground as the switching source is common on cars so that their failure mode is often on rather than off. But that also means flaky grounds can cause some real weird behavior.
 
Yep the resistor pack did the trick. Ford has a new replacement part that requires some re-wiring of the connector...and about $100 bucks of your money.

Thanks again for good advice fast.
 
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