HappyAdventure

I had lost all the fan settings in my pickup aside from high and off. High worked when I needed to get windows quickly defrosted, but is overkill for most everything else. I decided to replace the switch (relay and resistor were still working) but balked at the 75 dollar price tag for the little plastic part and decided to repair it instead. A long morning and a trip to the hardware store was all it took to get my blower switch working on all 4 speeds. The problem with the design of this switch seems to lie in an overly thin strip of copper leading from the contacts inside the switch to the pin for the connection leading out the back of the switch. On my switch that strip of copper had changed from being an efficient conductor to a little heating element. The heat from the conductor was able to melt and distort the body of the switch and char the connection. The switch can be accessed by removing the stereo and the faceplate for the climate control module. It is useful to also remove the bottom piece of the dash under the stereo to give a little more working room. You should be able to slide the switch back and out, then unplug it from it's electrical connector. After removing the switch from the dash I was able to pry the top from the switch at each of the 4 locking tabs around the edges using a thin knife. Be careful taking the moving contact out, there is a spring and ball bearing that will go flying (slip the pivot off, then ease up the spring pressure). Inside the switch the overheated piece was clearly visible - it was the lead and contact that completes the circuit for the speed below hi. It draws considerable current, but flows through the thinnest conductor in the switch.

I removed the piece of copper by pushing on the tabs that pass through the body of the switch; mine was pretty easy to remove because the holes in the plastic had enlarged due to the heat.

Once the copper strip was removed I pounded it flat and traced it onto a sheet of copper from the hardware store, then cut it out (make the thinnest part considerably thicker than the original). I cut it out using a small cold chisel pounding on a strip of steel. This left some pretty rough edges that I smoothed out using a dremmel. I then formed my new part into the shape of the original piece with a pair of needle nose pliers and a pair of standard pliers, then trimmed and smoothed it a bit more to make it fit back into the switch.



The wiring harness connector has also been destroyed by over heating, and rather than have it burn up again I soldered a wire directly to the contact inside the switch, and one to the wire leading away from the switch and added a spade connector to disconnect it in the future. The wire soldered to the switch can pass out the top with the light bulb leads, but the hole has to be enlarged.

Once the switch was back together it was still having some continuity problems as a result of the switch partially melting and warping. I was able to fix this by gluing a thin sheet of plastic (from some of that clear packaging that is really hard to open, a credit card was too thick) on the surface opposite the moving contact to increase spring pressure. You can test the repaired switch using a multimeter and seeing if there is continuity between different connector pins at different switch positions as outlined on page AC-37 of the FSM.

justin_4runner

nice job, when mine went bad i picked up one from a junk yard for 5 bucks and replaced it that way.. but like the idea of fixing it too.

swampfox

Very good write up .

wyoming9

iTrader: (1)

Just curious with all the running taking it out putting it back in and the repair how much time did you have in??

I must say Good write up!!

HappyAdventure

It probably took about four hours between running to the hardware store, getting it out of the dash and then figuring out why it still didn't work after the new contact was in.

noodles14

Excellent write-up! I'll be fixing this same thing once I get some other projects out of the way.

Lysmachia

Fantastic write up!

Toymind

Good job and good write up on the switch, now all that needs be done is for one of us to think of a way to repair the $$$ resistor pack that controls the blower speed so we dont have to pay 75clams for a new one.. This one im still thinking through...

HappyAdventure

Probably would be doable. I think you would just need to sting together a 3 high wattage resistors. If you could measure what the resistance is between terminals on the resistor pack and then get something like these. 3.26 each - not too bad. If you have your dead resistor pack out of your truck you might be able to crack it open and read the specs off of the resistors inside.

MudHippy

Right on man! Now that's exactly how I would have done that. And that's exactly what I will do too. If it turns out that's why my blower doesn't work on the lowest setting. If not, maybe I'll dig into that resistor pack and throw up some pics of that as well.

NCalDyer

very useful, i will rip into mine soon and give it a look-see

Brazos

Nice job. The '93 pickup I just bought has the same problem. Works great on HIGH or OFF with no in between settings. Now I know I can fix it.

aaajaaa

outstanding! thank you. i'm fixing my switch that way tomorrow.

toyospearo

great write up!

SDHNTR

Mine does this too. Pardon the newbie question, but where is this switch?

Geographer

The switch is directly behind the lever that you adjust to change your blower speed.

pistolbob

great post thank you.

dsleggett

$28 at AutoZone. http://www.autozone.com/autozone/par...questid=220986

HappyAdventure

Nice, how long has that been at autozone? That is a way better price than what I found at some other shops.

t4r2wder

@dsleggett thanks for that autozone part number. Big help.