Vent blower only works when switch is on "high". Help!

[imq707s]

I noticed this morning on the way to work that the vent blower control on my Mountaineer only turns on the blower when it is switched to the max speed position. The low and medium speeds don't turn the blower on. If I had to guess I would say that there are set of resistors either in the switch or somewhere else that went bad....and the only time the blower will turn in is when the resistors are bypasses (turned on high speed). Anyone had this problem before? Is the problem in the switch itself or somewhere else? My mountaineer is a 97', and had the three vent control knobs in the center dash console under the stereo. Thanks for the help.

 

[gijoecam]

I noticed this morning on the way to work that the vent blower control on my Mountaineer only turns on the blower when it is switched to the max speed position. The low and medium speeds don't turn the blower on. If I had to guess I would say that there are set of resistors either in the switch or somewhere else that went bad....and the only time the blower will turn in is when the resistors are bypasses (turned on high speed). Anyone had this problem before? Is the problem in the switch itself or somewhere else? My mountaineer is a 97', and had the three vent control knobs in the center dash console under the stereo. Thanks for the help.

It's probably the resistor pack or the wiring harness to it. I had the same problem a couple of months ago. I thought it was the resistor pack, but it turned out the harness and plug had melted down due to corrosion getting in there. The harness with plug and the resistor pack are available from the stealership for $30.

I think I posted some pics of it in my gallery in my signature.

-Joe

 

[imq707s]

Thanks, I'll have to check out your pics.

Where is the resistor pack located?

Thanks

 

[2manytoyz]

wheres the pics of the resisters?

 

[gijoecam]

Click the link in my signature. Then go to the Explore Pics from the pull-down. I thought I had more pics in there, but I guess I never posted them.... sorry. I got some pretty good pics of the repair, but it'll be the weekend before I can add them to the gallery.

In words, the resistors are under the hood, passenger side, on the front side of the blower housing. It's easier if you pull the one bolt out of the speed control servo and move it out of the way. I used a 1/4" drive ratchet and socket to get the screws out of the resistor pack. It's easier if you can move the washer fluid reservoir as I did the first time I changed them. It's not impossible without moving it, just a squeeze.

Hope that helps.

 

[briwayjones]

It could be the blower motor. A friend had that problem and that's what it was.

 

[imq707s]

If it was a bad motor....then is wouldn't work at all....right?


The blower does work, but only on the "high" setting.

 

[gijoecam]

If it was the motor itself, it wouldn't work in any position. In high speed, the relay bypasses the resistor pack. On the three lower speeds, the current passes through the resistors dropping the voltage going into the blower motor. In any setting, if the blower motor is bad, it won't work at all.

Odds are it's either a bad resistor pack, bad connection at the connector, or both.

Oh, and I forgot to mention something about my last post..... I used some silicone to seal up the outside of the new plug, and some dielectric grease to seal up the connections themselves. It should be pretty weather-tight now, and I haven't had any issues with the harness getting hot yet. It's nice having all four blower positions back now.

Now if I could just get to the one for the rear blower......

-Joe