Automatic climate control issues.

[robertn78]

Hello,

I have a 99 Mercury Mountaineer 4x2 with a 5.0. It is equipped with the automatic climate control. If you have it in full automatic, it turns that A/c on and runs the blower fan at full speed. When it gets close to the set temperature, it is suppose to slow the fan down and maintain the temperature. What it is doing is just turning off. When the controller asks for full blower speed again the fan turns back on. If I manually set the fan speed, it only works at full speed. When I turn the fan speed down even one tick, it turns off.
What is going on with the controller?

I remember there being a fix to the compass/outside temp display. That was just a re-solder the board which I was able to repair successfully. Is there a similar fix for this controller?

 

[robertn78]

What it is doing is just turning off.

I mean the blower fan turns off. The controller (User interface in the cab) works normally.

 

[koda2000]

there's a fan control module that sometimes goes bad. it's accessed through the engine compartment and is attached to the heater box near the fan motor. sometimes they can be taken apart and cleaned, sometimes you need a new one.

 

[Turdle]

 

[Turdle]

http://www.youtube.com/watch?feature=player_embedded&v=RUJ6Iiun7f4

 

[koda2000]

OP, you stated you have the automatic climate control (AKA EATC) in your truck. the ytube video supplied is more for the manual heater controls, but the module for the EATC blower fan is found in the same place as the manual blower resistor and often suffers from the same corrosion on the terminals.

 

[robertn78]

I will try to remove and clean the resistor tonight. Thank you for your input.

P.S. Koda2000 - I like your signiture.

 

[robertn78]

Is there a way to measure to see if the resistor is working correctly? I have a multimeter, but what should the resistance be?

 

[koda2000]

I will try to remove and clean the resistor tonight. Thank you for your input.

P.S. Koda2000 - I like your signiture.

thanks, i stole it from the guy on the Mythbusters TV show, put it often expresses how i feel.

i'm sure there's a way to test the fan module, but i've never seen one posted. about a month ago someone posted about how he took his apart and cleaned it (he said it was pretty dirty) and then it worked again. the resistor style used on the manual controls just reduces voltage with the help of several resistor coils. the reduced voltage causes the blower fan to spin slower. on the EATC system the blower fan seems to have more variable speeds, i'm not sure how the module accomplishes this, but it has to vary the voltage somehow. you always find the resistor in the heater box near the blower fan because it gets really hot (electrical resistance causes heat).

 

[robertn78]

on the EATC system the blower fan seems to have more variable speeds, i'm not sure how the module accomplishes this, but it has to vary the voltage somehow.

By a huge heatsink...

I think I found the issue...

I think the original died because of the dust on it and the LV heat couldn't cool that huge heatsink.
I bought 3 at Pick A Part for $10 and all 3 work. There seems to be an upgraded version with a different number. I had 2 of those so I used one of them since it looked newer. Thanks for all of your help!


Rob

 

[koda2000]

cool beans! glad you got it fixed.