Mechanics

BLOWER SWITCH

1994 Ford Aerostar

Heater problem
1994 Ford Aerostar 6 cyl All Wheel Drive Automatic 148000 miles

My front and rear heater switches, rear window defroster switch, and turn signals seem to work when they want to. They will work fine until I turn the engine off, then when I start it up, they won't work. They will not work for up to two or three days. Then all of a sudden they will start again. I have checked the fuses and they are fine. Any ideas?
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TCKC2
January 22, 2009.



Hi: It sounds like a bad ground. Start by checking under the hood, dash, vehicle for body grounds that may be broken or loose.

Let me know what you find.

Joe

I've looked all over and cannot find a bad ground. It is now doing something else. I won't come on until the van runs, for about 5-10 mins. It will then come on and work fine. It's almost like somethings in there that has to warm-up first, before it makes contact. Any ideas?

Tiny
TCKC2
Feb 20, 2009.
Hi: This is a tough one. The motor may be going bad or the actual ignition switch may be out of adjustment or going bad.

I am not too sure about the front one but I can tell you that the rear blower has a relay that is activated whenever the ignition is on by the thin blue lead. The orange or pink ones which are very thick(one of them is ground so be careful because the ground is what the control switches use along with watt resisters to provide current to the fan motor) anyway the orange or pink wire goes straight to the right side of the battery where there is a fusible link connected to a secondary
battery terminal (not sure what is is but it looks like a serious current relay). It is on the right side of the battery and is only an inch away from the positive battery terminal. Be sure to disconnect the negative battery lead before trying to check anything. I accidentally blew the fusible link and had to take the battery out to get it repaired. The relay for the rear fan is located about 7 inches below the rear fan control and to the right at 4 o clock angle and it is a transistor type relay on my 93 aerostar, for the front I would check both electrical leads to the blower motor for both +12v and ground though.

Tiny
Aerostar4
Feb 26, 2009.