I have a 2000 e150 and the ac / heat fan speed switch on the front dash is missing its "3rd" speed control. the switch has 4 speed positions. Lo, med, med hi and Hi. Low, med and Hi all work fine. no issues with the rear control. already replaced the resistor under the hood in the evap box and no change. Just looking for other insight before I take the dash loose and try to get the switch out.

 

Well I got anxious and tore into the dash. Not too bad to get around. Found that it helps to remove the radio for more working area around the fan speed switch. take 7mm to remove dash and AC control pod. 1/4 inch to remove fan speed switch.. Found that the 3rd position on the switch must have gotten too hot. Some plastic from the switch body had melted on the metal contact. Cleaned it off and all is working now. Will have to watch it for why it got too hot. Hope this helps others.

 

I've had this same thing happen---the reason never discovered. Mine simply overheated, left that hot/melted plastic smell and the blower stopped working. Replaced the switch and the same blower motor is still working just fine.

Typically had there been an issue with the blower it would have failed even with the new switch. The fuse should have also blown----not the case for either of us it seems. I'll bet we're not the only two to have experienced this though.

Access to the heater controls requires a bit of removing dash parts but not too bad----not after you've done it a time or two!

 

tried cleaning mine and it worked for a while. ended up buying a new one. that one was easier to put in since I knew how to do it now!

 

Boy, Howdy ain't that a fact!

First time tearing into the dash of anything after '97 its a head scratcher for sure. Its a cruel irony most of the electrical bits are behind that middle section which means everything to the left has to come off or out first. During a project on my '00 E250 I ran around for almost a year with the speedo bezel off---just in case I needed back behind it again!

 

I just fixed a similar problem on one of our ambulances. Web research kept turning up suggestions that the resistor needed to be replaced, but all of the problems noted the fan only working on high speed, regardless of the speed selected on the switch. Our truck was only blowing on low, regardless of the fan speed selected. After replacing the resistor, I changed the switch. The connector had melted onto the posts on the switch. With a new switch and connector, it works fine and we finally have high output on the air again! The new pigtail came with wires, but rather than butt-splice the wires, I removed the new ones by releasing the plastic catches inside the connector and installed the old wires in their appropriate places.

 

Repairing or reconfiguring the plastic shells is a bit fun IMHO! I've added a few mods to my wiring and wanted to maintain some of the factory wiring or have that same appearance and convenience so decided to tool up and stock a few of the more common Ford terminals.

Now I'm able to add or remove connections pretty much anytime. This was a good move, makes for a cleaner, more professional installation or repair.

 

I believe mine just went out.
at the old shop, we had a '96 & a '00 e250
each switch went out at about 4 years of running,
mine is a '99, hope it is just the switch,
it is frigid outside, ;(

 

On mine it was the third speed setting that went out but had to replace the switch. If you're relatively handy it's no big deal. If you don't have the tool to remove the radio, you can fashion one from a coat hanger (u-shaped) to release the hold-downs for the radio

 

If the switch and or plug is melted/burned/overheated, it is a good bet that the a/c blower fan is wearing out. The switch **** area can be quite warm to the touch. The blower may draw a lot more current when it is close to the end, wearing out. I had repaired, then replaced the switch before, and it still was warm. 6 months later the fan quit. With the new fan, the switch runs much cooler.

I do not know the amps of the normal ac blower but a clamp-on DC ammeter is $65 today and the current of a normal fan can be checked at the blower.. so someone may wish to do that and post it.