Sometimes my blower motor will not go to a higher speed when I turn the switch. Is there a relay somewhere that controls the speed of the fan? If it doesn't speed up sometimes it will when the car accelerates.

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'89 Formula 383 TPI

 

Greg,

Yes.

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Later,
Vader
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"Make Me Bad"
Adobe Acrobat Reader 4.0

 

Where is that relay located?

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'89 Formula 383 TPI

 

Vader..."YES".........LOL

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ASE Mechanic/Machinist/Smog Tech

1999 NBM Trans Am
1986 Chevy 3/4 ton pick up
1981 corvette
1995 Kawi ZX6R

GO #3

[This message has been edited by Engineboy (edited September 25, 2000).]

 

Follow the purple wire leading away from the blower motor. It will go into a plug that plugs into a black box. That is the relay.

They rarely go bad. What usually causes that problem is a connector that carries the battery to the relay. Follow the red wire from the relay as it goes toward the driver's side. About at the right valve cover you will find a burned-up connector.

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"So many Mustangs, so little time..."

 

Check the Blower Resisters.

This should be a four wire plug (I think) to the right of the blower motor (looking at it from the front of the vehicle)

It will look like the plug just goes into the heater box.

Should be two bolts holding this on. (I think they are 5/16)

Remove plug, remove bolts, and you will pull out this thing with 3 coil windings on it.

If any of the windings are broken or burnt off, this is your problem.

A bad resister will cause the fan to run only on certain speeds.

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ASE Mechanic/Machinist/Smog Tech

1999 NBM Trans Am
1986 Chevy 3/4 ton pick up
1981 corvette
1995 Kawi ZX6R

GO #3

 

I second Engineboy's idea... they burned out on my friend's 1991 Formula, and a month later mine went out too. Junkyard = free.. I guess the guy didn't want to write up a receipt for it.


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-Tom P (Hot rodded 1986 Firebird 2.8l) from http://www.f-body.net/mailbag/3rd/3rd_mailbag.html message boards

 

OK, I'm taking this to a new level now. The wipers have the same problem. Sometimes they won't work unless I put it to the high setting and then I can adjust it to whatever speed. The problem has to be related to the blower switch because I was accelerating and tried the wipers again without putting it to high and they came on. So there has to be a bad connection somewhere that operates the wipers and blower switch. Anybody know where a common link is?

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'89 Formula 383 TPI

 

Greg,

Studying the schematics, I don't see a common point between the two circuits. they don't even start from the same bus feeder in the fuse panel. The wipers are on the node fed by the #8 AWG brown feeder and the HVAC controls are fed by the orange #8 AWG feeder. The brown feeder is sourced at ACC #4 terminal, and the orange feeder is sourced at the IGN #3 terminal. The only common connection is at the power distribution block abive the left kick panel and circuit 35 at the Fisher bulkhead connector at the firewall. If you had failures at either of these points, you would likely have problems with the courtesy lights, radio, instrument lamps, headlights, directonal signals, and brake lights, among other things.

I think you have two separate problems.

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Later,
Vader
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"Make Me Bad"
Adobe Acrobat Reader 4.0

 

Greg,

The wiper problem is probably the integrated turn signal/cruise control/wiper control lever. I had the same problem and replaced the lever and no problem. The heater was the same problem as yours and it was the relay.

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'87 Formula 350, Nothing Special Yet