Mechanics

NO HEAT

1997 Mercury Mountaineer

Heater problem
1997 Mercury Mountaineer V8 Four Wheel Drive Automatic 125k miles

1997 Mercury Mountaineer, Heat problem. Occassionally a delayed flapper could be heard opening from underneath the dash and then the blower would come on. The Blower had only worked on high speed setting. Now Nothing! No Blower, No Flapper noise. No Heat At All. Any Cure?
It appears to me the blower motor is controlled by the flapper opening. Sometimes the rear heat will blow warm without the front blower actually operating.
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Rjmillsbjkl
December 7, 2009.



When your blower motor was working in only one speed "High". It is very possible your blower motor resistor is either stuck or needs replacement.
If you can repair it yourself that will save you some money. Here is what you need to do.

Remove the speed control servo.
Disconnect the electrical connector.(1)
Remove the bolt. (2)
Position the speed control servo (3) aside.


http://www.2carpros.com/forum/automotive_pictures/433905_Servo_Motor_1.jpg



Remove the coolant/washer reservoir.
Remove the two screws and the two nuts. (1)
Move the coolant/washer reservoir (2) aside.


http://www.2carpros.com/forum/automotive_pictures/433905_Windshield_washer_res_1.jpg



Refer to the sketch below for the blower motor resistor location.
You will see the blower motor resistor (1) just below the vent hose. The arrow is pointing at the blower motor housing.

Turn the heater fan speed selector on "High".
Turn the ignition "On" but do not start the engine.
Get a long screwdriver or something similar and place it against the resistor housing.
Give the resistor a slight tap, listen to see if the blower motor is working. If it isn't, give it another tap.If it is not working, give it one final tap.

If the blower motor is still not working the resistor needs to be replaced.

To remove the resistor:
Disconnect the electrical connector from the resistor.
Remove the two small bolts.
Remove the resistor and replace it with a good one.

You can buy the resistor "new" at an automotive parts store or if you have a "Junk Yard" or "Auto Salvage Yard" near you, you can pick a used resistor up from them and save some money


http://www.2carpros.com/forum/automotive_pictures/433905_Blower_motor_resistor_copy_1.jpg



I hope that helped you out;
Rick
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Tiny
RickMar
Dec 9, 2009.
Thank you Rick for your detailed response. I had to run to the junk yard to grab a three knob controll for inside the vehicle because I had broken one of the knobs, As I was there I did grab a resistor from that vehicle and installed it. The problem continues! No Fan. So, I ran a wire from the battery to the blower motor as it was in place and spliced into the positive wire of the blower to see if the blower would work. The blower works. (High Speed of Course)
Some where between the inside fan control and the blower I've lost power to the blower. I followed the blower motor wire to the frame of the vehicle to a black box with three or four contacts inside, which is located on the passenger side closer to the front of the vehicles frame. Could my problem be locate in this black box? And would the resistor I replaced it with be bad too?

As I said I spliced into the blower motor wire from the battery and the blower can be controled from off to on (high speed) from inside the vehicle. I naturally want to control all the speeds and I'm still looking for a solution to the blower not responding to the setting inside the vehicle. As I mentioned before I believe, the blower does not operate on any speed that was set inside the vehicle. It use to work only on high speed before, it stopped working completely.

Fuses inside have been checked

Thank you in advance for your help and expertise!

Tiny
Rjmillsbjkl
Dec 11, 2009.
Hi rjmillsbjkl ;
The problem "possibly could" be in that black box.

The resistor is usually always the case 9:1.
There just might be "very slight" chance of (1 out of 9) you did pull a bad relay out at the junk yard.

You mentioned that you grabbed a three knob control so you "do" have the correct resistor that goes with that configuration.
Some mountaineers have a digital "EATC" (Electronic Automatic Temperature Control) and the resistors electrical connector is a little different than the knob type.

I'm thinking the electrical connector may be giving you a problem but not sure... The (resistor you took out of the junk yard)... is it identical to the one you replaced ?
It is now narrowed down to the resistor/ wiring harness/ black box. We have not ruled out the blower motor completely but we should throw that in too just in case.


http://www.2carpros.com/forum/automotive_pictures/433905_1997_explorer_blower_motor_1.gif



Just giggle electrical connector (2) in the sketch above and see what happens.... I will be back later on today.

Rick

Tiny
RickMar
Dec 11, 2009.

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