Hey all, I've been around a while but usually lurk in the background. I have read many posts on the blower motors not having any other speeds other than high. Naturally, the simplest fix is to replace the resistor pack. To those who like to dig a bit more, simply remove the resistor pack from the a/c case, and using a multimeter, check for a bad diode. In every case that I have seen, its the diode that has failed. The fix is super simple and cheap, far less expensive than a new resistor pack. Upon finding the failed diode, a new one can be bought at Radio shack. Simply cut the old one out, and solder the new one in. This repair should cost you less than 2 dollars to perform. Mines working great with it's original resistor pack and a soldered in diode. Just my 2 cents worth. Any other questions, feel free to PM me or hit me up on AIM. If need be, I can give a few pics to make it simpler.

 

whats your vehicle? ours is a 2002 ses taurus, did the diode trick, also made up the rain cover so it doesn't happen again(so blower motordesn't get rained on)

 

My vehicle is a 2003 Super Duty F-250. I've done the diode trick to several, but thats the only vehicle that I have ever done it to that I personally own.

 

I have a 2005 4x4 6.0psd supercab F350 long box, i didn't know the superdutys had that problem.

 

Unfortunately, its a problem that exixts on many makes and models, not just Ford. Its old school technology that for the most part works well. Just trying to save a few people a couple of bucks and learn something too Also, being here in Louisiana, we tend to run the a/c practically year round, so we tend to test components such as this a little bit more than people up north of us do.

 

Thanks for that - I put it in the tech folder

 

I have a 99' f-350 will that work just the same?

Thanks
SGT

 

Oh i made a mistake, its not a diode its actually a thermal fuse.

 

I just had the blower on high problem on my 2006 F250 FX4 with EATC. I replaced the only diode on the board but it did not fix it. I think it may be the Darlington power transistor. Still cheap but not sure if that is it.

I had stopped at one dealer in my county and was quoted almost $90 for the blower controller. Stopped by another dealer and got the almost same part for $52...beware dealer pricing!!!

This did the trick.

 

I have '05 SuperDuty. High Blower Problem popped up. I pulled the blower control unit out, and replaced the Darlington Transistor. It took about 1/2 hour. If you can do a little soldering, it's very simple to do, except for the stupid location of the bottom screw holding the unit in.
The part was 17$.

 

Thanks, 86EddieB. I just replaced the evaporator core and accumulator in my '99 F-250 this weekend and noted that I had the High-Only fan speed problem. i was thinking I might have to buy something expensive but decided to do a check of this forum first. I have to admit that you guys have saved me some serious money since I bought this truck back in '02. I've only had to do a couple simple jobs but it has helped my confidence immensely to be able to check here first. This is my first diesel and I still dread the very thought of having to do serious engine repair but I know I can come here for really good advice. This time, from a fellow Cajun. Thanks again.

 

it is the thermo resistor, about $14 bucks and ten minutes to replace under dash

 

For us non technical/without a service manual owners, where is the thermo resistor located? or the diodes? Are they under the dash on the switch, or in the engine compartment on the motor itself? Thanks for any help provided.

 

1999-2002

 

Thank you for the excellent photo. My truck is an "05", I assume it is similiar to the 1999-2002 you photoed? The resistor removes from the engine compartment side or from under the dash? I only ask because I read the other posts and they talk about removing it from under the dash, and that picture of the wiring harness connector is from the engine compartment, I believe. Also, where do you buy the resistor, Radio Shack? Do they have numbers for sizing or fitment?