heater on full or none

[dillon1340]

my blower for the heat is either on full or not on at all; there is no in between speeds. does anyone know where to begin a troubleshoot on this for an explorer?

 

[boggs1227]

the blower switch (dial ) ? if not mistaken the switch operates off of resistance ...off the circut see's no power...on or first click ,there is a resistor in the circut that cuts down on the power going to the fan motor ( or highest resistance) .next click upward till you get to full blast is a process of going down in resistance till you hit full blast.


chances are that the switch has gone out but i'm not sure if the resistor part of the circut is located inside the dial unit or like on my 2005 colorado when my blower switch went out ,the resistor was a separate unit module located inside the dash.


hope this helps if any . . . . .

 

[fixxxer]

It's the blower resistor, inside the blower housing, passenger side engine compartment, next to the firewall

 

[Maniak]

Look at the heater box from under the hood. Look at the side of the heater box that is towards the fender (passenger fender). You will see a plug going into the side of the box. That plug is connected to something held in by 2 screws.. Thats the blower motor resister. When that goes bad (coil breaks) the fan will only work on full power.

Two screws and that connector and you can see if its broken (and or replace it)..

~Mark

 

[boggs1227]

mm'yeah ...what they said ....guess iknow where to look now if mine goes belly up

 

[fixxxer]

http://www.explorerforum.com/forums/showpost.php?p=1951019
There's a thermal overload fuse in the low-speed circuit that goes out.

 

[dillon1340]

wow. super information. i will check it this weekend. thanks!

 

[dillon1340]

resistor fixed problem. once again thanks to this forum!

 

[justchillin]

thanks for the troubleshoot. just replaced the blower motor resistor and I have all my fan speeds back!!! It stinks havin to change it in 26 degree weather though!!!

 

[prince402]

This may save you the $30 cost of a new replacement resistor or $4 for a salvaged one and save you the running around to get them.

So far I have removed the resistors from two different 94 Explorers where the blower only worked on High Speed. In both cases the male spade terminals on the resistor assembly were very corroded with white and rust colored powdery deposits. The female plugs looked OK.

So I used a #2 pencil to burnish the corroded male terminals, pushed a little grease in the female terminals to prevent further corrosion, put it all back, and they worked fine. It was the corroded terminals and not a failed resistor.

The #2 pencil is a good way to clean electrical connections. The so called "lead" in the pencil is a mixture of clay and graphite. The clay burnishes and the graphite coating is an excellent electrical conductor. If you want more burnishing go to a #3 lead pencil and finish with a #2 or #1 for a good graphite coating.

Following the advise in this forum on fires in the resistor air channel, I removed about five curled up dried leaves the last time around. Also the resistor is very easy to check with your multimeter; just ohm it out.

 

[MontanaTom]

thank you everybody!! Just what I needed!!

 

[kmack]

Having this same issue...
Blower is only working on high (no other fan speeds). I pulled the resistor pack out and it does not appear to have any broken coils on it. How can you test it?

Also, I pulled the blower motor out. When spinning the blower by hand, it makes a little squeaking noise as it stops. Doesn't seem to have a lot of resistant to turning, just makes noise. Looking at the windings inside the motor, nothing looks dirty or burned. Looks really clean inside.

Anybody have any other suggestions?

 

[natenkiki2004]

The motors start to chirp when they get old/worn. If it doesn't do it when you run it, don't worry about it Your issue has got to be in the wiring or in the resistor. If you know how to run a multimeter on it, you can test for ohms or voltage when you turn it to various settings.

 

[kmack]

So I went and bought a new resistor pack - about $28 after taxes. Got it home and put an Ohm meter on each of the coils. Got a reading on each one. Then I tested the old one. I could only get a reading on one coil and the little resistor.

Put the new one in the truck and everything is back to working like normal!