Solved - Blower resistor on '99 Mountaineer | Ford Explorer Forums - Serious Explorations

  • Register Today It's free!

Solved Blower resistor on '99 Mountaineer

Prefix for threads that contain problems that have been resolved, and there is an answer within the thread.

camerafool

New Member
Joined
January 13, 2010
Messages
5
Reaction score
0
City, State
MN
Year, Model & Trim Level
'99 Mountaineer 4.0 4wd
Only the highest speed works on my air/heat and everywhere I look, it seems the blower resistor is my problem. Where is it located on a '99 Mountaineer? Also, I went to a parts shop and there are two resistors they offer...one is a $15 resistor and the other is $100 resistor module. It's a '99 mountaineer with 4 wheel drive and has automatic temp control. Do I need the $100 module or just the $15 resistor? Any help would be greatly appreciated. Thanks!
 



Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!
.











Only the highest speed works on my air/heat and everywhere I look, it seems the blower resistor is my problem. Where is it located on a '99 Mountaineer? Also, I went to a parts shop and there are two resistors they offer...one is a $15 resistor and the other is $100 resistor module. It's a '99 mountaineer with 4 wheel drive and has automatic temp control. Do I need the $100 module or just the $15 resistor? Any help would be greatly appreciated. Thanks!

Automatic temp control is going to make your wallet $100 lighter. The other thing you can try is this (wish I did it before I bought mine). Take out the failed unit and clean it with parts cleaner. You may have a loose solder connection. You can also bring it to a TV repair shop, they may replace the power transistor for $20-30 dollars. Its not a complicated circuit. Just a thought!
 






please forgive the silly question...I'm new to auto repair. Is the firewall that shiny aluminum-foil-looking thing? If so, what's the best way to get around it and access the resistor?

Also still curious on the question of which resistor part I need. Thanks for the quick reply!
 






that's great advice 96eb96. Now I just have to get to the resistor! haha. Thanks!
 






Automatic temp control is going to make your wallet $100 lighter. The other thing you can try is this (wish I did it before I bought mine). Take out the failed unit and clean it with parts cleaner. You may have a loose solder connection. You can also bring it to a TV repair shop, they may replace the power transistor for $20-30 dollars. Its not a complicated circuit. Just a thought!

Yep, misrerad my manual. EATC does not have a blower motor resistor for the front motor, only the rear.
 






that's great advice 96eb96. Now I just have to get to the resistor! haha. Thanks!

Well look for the fan on the passenger side, it is buried toward the bottom. It is a bit tricky to get out as I recall, you may have to take off the harness first.

Also, what happens when you turn the control wheel? Does it only run at the max setting or is it always running on high???
 






on both the control wheel and the controls on my steering wheel, only the highest fan speed works. If i turn it down one speed, the fan stops all-together.
 






on both the control wheel and the controls on my steering wheel, only the highest fan speed works. If i turn it down one speed, the fan stops all-together.

Hmm..I'm not ready to implicate the fan controller yet. That device receives a low power signal from the head in the car and "amplifies" it using a power transistor to run the fan. The head may only be putting out a full power signal.
 






Well here is the test to determine what is bad:

Adjust the blower motor speed to LO (1 bar).

Measure the voltage between the EATC module C298 pin 23, circuit 181 (BN/OG) and ground by back-probing the EATC module C298.


Is the voltage greater than 1 volt?
Yes
INSTALL a new blower motor speed control. TEST the system for normal operation.

No
INSTALL a new EATC module. TEST the system for normal operation.

I would take the fan controller out as well to see if its burnt or damaged, probably likely that is the issue.
 






I'm really confused. Everything I've read about the problem I have says that it's most likely the blower resistor. What changed your mind on that?
 






I'm really confused. Everything I've read about the problem I have says that it's most likely the blower resistor. What changed your mind on that?

MOST LIKELY it is. But there is a chance that the EATC is only commanding a signal for a high blower output only.

99% of the time that blower controller does fail though, but be aware of the test I posted in the above post. The test will verify a low power signal for a low setting.

Usually the blower controller will show a visible sign of damage.

Just want you to understand before you just replace parts!
 






I'm really confused. Everything I've read about the problem I have says that it's most likely the blower resistor. What changed your mind on that?

The problem is that if you have the electronic automatic temperature control, you don't have a blower motor resistor. You have a blower motor speed controller (a little black-box that electronically controls the fan speed) in place of the resistor pack. That's the difference between a $15 resistor pack and a $100 module. I'm assuming that since you have the controls on the steering wheel, you have the EATC.

The odd thing is that usually when the blower motor speed controller dies, you lose ALL fan speeds. I've not seen one fail, yet still allow it to work on high... that's kind of odd... I'd start with 96eb96's diagnostics and go from there. I'm personally leaning towards it being a EATC module issue, not a speed controller issu, but I honestly don't know which it would be.
 






Same fan problem: only works on high

I have the EXACT same problem with my 99 EB Explorer with EATC. I keep hearing all the same things and am torn between looking for a resistor pack, (which I'm leaning towards the advice above that it doesn't exist on my model) or the Blower Speed Control Module. I live near a Pull-A-Part and there's quite a few Explorers so I don't mind scavaging several $5 used parts and start swapping just to learn and hope for luck...Camerafool, if you find the answer and get yours working, please post how. Thanks
 






Again, if you have the EATC, you do not have a resistor pack, you have a blower motor fan speed controller. Why is everyone making this so complicated? You have either EATC with a fancy electronic control unit and BMFSC, or you have three knobs and a resistor pack. The two systems do not mix.
 






Where exactly is the EATC blower motor fan speed controller located?
 












Well that was pretty easy.
I ordered the Rock Auto RU539 blower part, it arrived yesterday and probably took me <20 minutes to install it. Blower runs perfectly now and my "Check Engine" light which had come on three days ago went out as well.

The easiest way to install it was to:
-remove the air cleaner and the lower air cleaner box
-remove the cruise control servo
-remove 4 bolts holding windshield washer/coolant container and slide it forward about 6"
-remove and replace 2 bolts holding the blower module assembly
-reassemble

What is strange is that the EATC test procedure (press OFF and FLOOR simultaneously, then press AUTOMATIC within 2 seconds) never revealed any fault codes when the blower module was having issues or even after the Check Engine light came on. (?)

Oh well, everything is working fine now.
Thanks for the help as always.
Tim
 






what i've learned...

blower motors don't have any way of varying fan speed. since the 50's, vehicles have used something called a blower motor resistor to vary the voltage going to the blower motor. this in turn allows the blower motor to run at different speeds (usually 3 low/med and high). by their nature resistors get hot. the blower resistor gets very hot. to protect your vehicle from catching fire, the resistor lives inside the heater plemnum. this way it can't come in contact with any other parts and is cooled by the movement of air created by the blower fan.
 



Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!
.





what i've learned...

blower motors don't have any way of varying fan speed. since the 50's, vehicles have used something called a blower motor resistor to vary the voltage going to the blower motor. this in turn allows the blower motor to run at different speeds (usually 3 low/med and high). by their nature resistors get hot. the blower resistor gets very hot. to protect your vehicle from catching fire, the resistor lives inside the heater plemnum. this way it can't come in contact with any other parts and is cooled by the movement of air created by the blower fan.

A blower resistor is used for the MANUAL controls. The ELECTRONIC controls use a blower motor speed controller, which works differently but accomplishes the same function.
 






Back
Top