hi ive recently bought a 1987 bronco xlt with the 302. im new to the forum any how on to the problem. (i did a search but didnt find what im looking for)

the problem ive been encountering is with the heater blower switch the one that regulates the speed of the blower (lo-hi). mine was only working on hi so after several trips to the parts store and a week later i get the right part because they had the wrong part in theyre system. i replace the switch with no avail except now i dont even have high. part number for the switch (E5EH-19A642-AA).

so doing some further research i find out that the heater core resistor could be burned up so i order one of those and go to replace it but when i pull the old one out none of the coils are burned up. so i dont know where to go from here. im going to put some vaseline on the spades on the resistor to see if it lost connection and see if that helps.

to conclude:

heater switch only works on high
replaced with new one with no settings working
ordered new heater core resistor, but old one was still good.

so whats next...

thanks in advance for any help.

andy

oh one more thing i noticed in the parts store catalog that they had 2 versions of the switch for my year model anyone know whats the difference between them?

 

Inverse, welcome to FTE. The problem your having sure sounds like the blower motor resistor, when the resistor fails the fan defaults to high speed, your windshield wipers will do the same thing. It could also be the wires themselves.

 

Like 94 xlt said it sounds like your in the right direction. but,
If the new switch is not even running hight then that switch is defective and you need to take it back.
I would install the new resister just to see if that fixes it.
After you put your old switch back in.

 

thats what i thought too and the first switch i got i returned because it wasnt doing anything then after recieving the second one it still didnt do anything so then i was told to check the resistor. i think im just going to replace the resistor even tho the old one looks to be fine and see what happens. also as for the switch not working could it be that i ordered the wrong one? there were two versions of the same switch. i believe the catalog they had was called sorensons?

anyway thanks for the info atleast i know im in the headed in the right direction.

 

I went thru a similar situation with the wiper switch on one of my 79 f250's. I took out a switch from a parked truck to put it in one I was driving. The SuperCab needed one that had several speeds and the donor switch had fast and slow. It could be made to work, but would not just plug right in, if I'm recalling correctly.
My point is that I would think if the switch were the wrong one, that it wouldn't just plug right in. But I could be mistaken on that too.

I don't know how to test the resistor, but I'm certain it could be done. But if it's cheap enough and you already have the stuff taken apart, I'd go ahead and change it like you're planning on doing anyway. That way you know that part is done.

 

Not sure on your resistor but some of them have a thermal limiter built in. Looks like a metal diode type thing. It is just a type of fuse and if it goes out you'll have to replace the resistor. Did you check to see if you have power, might have blown a fuse while replacing parts.

 

Its ws the resister. I've replaced several on my trucks and never replaced switch. 4or 5 blowers,and 1 blowe cage. I live in cold zone so always changing blower speeds. Had trucks close to 200000 never problem. good luck If went to ford garage they would have said to swap right offf. And the price is so close to my local mega auto store I use oem parts most of time.

 

So where is this resistor? I'm having the same trouble right now, blower only works on high.

 

the resistor should be in the engine compartment next to the blower motor.

 

yeah it was the resistor it may look like its ok on the outside but man was it rusty on the inside it was a PITA to get apart.

 

Is it possible to get a bad resistor? I am having the same problem. I replaced my switch AND resistor and it still only works on high. I cant find any other part that has to do with the blower motor speeds. I figured it is not likely to get a bad resistor, right? Is that the only thing it could be? My old one was definitely bad. It was rusted all to heck. But this brand new one?

 

as far as i know those are the only two things that can cause it to work on high only. you said that yours was badly rusted maybe the recieving end of the resistor is also to far corroded and may need to be replaced.

 

oooohhh..okay, thx inverse. By receiving end, you mean the wire harness? I did look at that, but It didn't look too bad. I did have to break the old resistor off of the harnes and shot some WD40 down in there (don't know if I'm supposed to do that or not). But, if I check that and it still doesn't work, how would i check the resistor with an ohm meter to see if its good? Do you know what it should read?

 

yeah i had to break mine off to. i do mean the harness. the one terminal on mine is corroded away so when i replaced the resistor i got back low and high but no medium because of the corroded terminal. the wd40 shouldnt have an effect. as far as the checking the resistor i dont know much bout that and cant really help you out there. maybe someone else will tune in and let you know what to do.

andy

 

[QUOTE=inverse1216]yeah i had to break mine off to. i do mean the harness. the one terminal on mine is corroded away so when i replaced the resistor i got back low and high but no medium because of the corroded terminal. the wd40 shouldnt have an effect. as far as the checking the resistor i dont know much bout that and cant really help you out there. maybe someone else will tune in and let you know what to do.

Ok. good info. thanks andy. i will chk out my harness just to make sure.