Is there a hidden little jobberdo or trick?

[Tom7227]

My 2002 F150 fan suddenly only works when the switch is placed in at the highest speed. The three lower speeds settings don't cause anything to happen. Switch, fan, or some hidden little jobberdo or trick to fix it.

As always, thanks for your time.

Tom

[Jeremy airjer W]

This is usually caused by a blower motor resistor that has gone bad. Typically the resistor for the speed just under high has burned out. Since all the lower speeds rely on this resistor to control there speed they also don't work.

[Tom7227]

This is usually caused by a blower motor resistor that has gone bad. Typically the resistor for the speed just under high has burned out. Since all the lower speeds rely on this resistor to control there speed they also don't work.

And to repair this problem could you tell me which little jobberdo needs to be replaced, or where the errant resistor hides. Is this a Tom do or a you do? Tom has a fairly high skill level at fixing things and most of the time they work, or will after he's tried a second time, third at most.

[Surface Tension]

I think yours will be under the glove box.

[Jeremy airjer W]

Yup, They are typically near the blower motor. Usually held in with two screws, and usually have around 5 or 6 wires going to them.

[Tom7227]

<a href="http://s256.photobucket.com/albums/hh186/Tom7227/?action=view&current=IMG_0001.jpg" target="_blank"><img src="http://i256.photobucket.com/albums/hh186/Tom7227/IMG_0001.jpg" border="0" alt="heater"></a>

Well the Haynes Manual agrees with you AirJer but the truck doesn't. There are two cannon plugs in the area - one has 2 wires that plug directly into the heater motor and the other one has 5 wires and was attached to the motor housing with a hanger. No neat little brass colored resistor as it shows in the Haynes. I have tried to attach a photo but won't be surprised if it doesn't work.

The male side of the cannon plug with 5 wires has a red piece of plastic inside it but it appears to just be a spacer. Nothing visible like the Hayne shows.

I know I'm pressing my request, but do you have any other ideas?

Thanks

Tom

[Tom7227]

Here you go for the picture

[Jeremy airjer W]

Its in the plenum behind the glove box somewhere. Possible above the arrow?

[Jeremy airjer W]

Should have and orange with black, Lt green with white, Yellow with red and a black wire at the connector.

[Tom7227]

That one leads to the thermal limitor (at least that's what Haynes calls the piece.) The other set of wires leads up into a huge bundle that has to be part of the wiring harness. If I have to get much further into the dash I'm going to have to lose about 50 lbs. Pic is bad focus due to cramped conditions.

[Tom7227]

Well I took part of the dash apart and the wires from the blower controls go into a bundle of wires and disappear into a spot that can't be seen and a place that may require the entire dash to be taken apart. Baffling.

[Jeremy airjer W]

That one leads to the thermal limitor (at least that's what Haynes calls the piece.)

That's it! Take it out. if it has a few curly looking wires it is the part you need to replace.

[Tom7227]

Another satisfied customer of AirJer's advice. His assistance got me past some bad info in the Haynes Manual and after a lot of squirming under the dash I managed to get to the right part, get it out and install the new one. The old part was terriblty corroded and that's a mystery since the truck is garaged all the time and there is no evidence of leaks anyplace on the heater plenum or interior of the truck.

Thanks for the help AirJer

[Jeremy airjer W]

That is normal for that part. It has some extreme heating/cooling cycles and it constantly gets blown on by the air coming into the vehicle whether its raining, snowing, or sunny!

[BoxMN]

Thanks in advanced to you guys, as I have same issue on a 98 Malibu. Will it look pretty much the same, in same location?

Thanks!

[Big Buck Buster]

Thanks in advanced to you guys, as I have same issue on a 98 Malibu. Will it look pretty much the same, in same location?

Thanks!

It is located on the passenger side up underneath the plastic cover. Remove the cover, and it will be in the same housing as the blower motor. If it hasn't been replace yet, you might be getting a different version. The first models are made of a printed circuit board. If you get the updated version, you might have to modify the opening where the old one came out of to make room for the new one. Just a little trimming of the plastic is all it takes. Not hard to do.

Good luck.

[Tom7227]

Box,

You're going to have to lose weight to get the job done. Essential tools include a trouble light, a flashlight, a mirror and a digital camera so you can poke it up there, take a picture and then see what the deuce you're supposed to be looking at. Finally you will need a hot tub cuz you'll be in knots after each step of a 7-12 step process. (first 6 to 11 are merely exploratory actions.)

Good luck.

Tom

[BoxMN]

Ha! after that info, I am afraid my Malibu might become my casket - they will have to leave me there when I get stuck!

Thanks guys, I will give a try or two anyway, and will have a hottub on standby!

[Jeremy airjer W]

Don't forget to pick up a 5.5 mm socket to get the screws out! If your really lucky they will be plastic welded to the air box. Once you bust the welds on the old one there will be spots to screw in the new one. The new resistor will not come with screws!