[MTBRONCO]

you know the switch that controls the speed of your heater fan ??? from low,med,high????? i only have high how do i fix this problem i got the bronco like this please help it would be nice to have low heat sometimes or low ac just got hi

 

[jermil01]

What year Bronco do you have? There is a cable that runs along underneath the dash that controls the fan and the heater. I believe it runs to the heater blower box. Check this something might be not be right there. Or it could be that you have a bad switch.

 

[Dustball]

The exact problem you have is that the thermal limiter on the blower resistor pack has blown. When that limiter blows, the electrical current bypasses all the resistors and gives direct voltage to the blower fan, high speed. The resistor pack is located on the blower motor housing in the engine compartment, held on with two screws. Look on the housing between the blower motor and the fender and you'll see a 6-wire electrical connector plugged into the resistor pack. I've had a few go out on me, easily replaceable. I just go to the junkyard and grab a couple, they're on every Ford truck and van out there.

 

[ValkariaKid]

I've had this happen twice. Once on my '84, and now on my '89.

Both times the back of the fan switch was melted.

Take a look at your switch.

 

[GusDaDog]

while searching for the answer to my problem I found this post... I recently took my Bronco out of storage and the fan only worked on high speed (86 Eddie Bauer) and the blower fan was really loud and now I don't have any blower at all! Think my resistor pack went back and then blew out my blower too or what? I need this fixxed ASAP but got laid off 2 weeks ago and don't have a ton of cash to blow...

thanks!

 

[GusDaDog]

should I replace the resistor only, test it, then the motor? What can I expect to pay at a parts store?

 

[miesk5]

yo,
and thanks to steve; here is a res. pack pic:

here is the url for the pic since it won't post:
http://www.superford.org/registry/vehicles/showmedia.php?id=71638
Take a look at the fuse, switch then pack (iaw w/ease of looking) beofre buying or junk yarding any parts. Prob is the res. pack from the sequence.

 

[GusDaDog]

I checked my fuse and it was still fine however it had a 10amp fuse in instead of a 30..hmmm

they have the fan motor in stock across the street at AutoZone for $29.99 which seems like a good price but they don't have a resistor pack which is upsetting. I can't imagine my dash switch went bad but for $5 should I replace it anyway?

keep in mind the motor was significantly louder than usual when I only had high speed, I'm talking 3 or 4 times as loud as usual....

 

[GusDaDog]

I found my resistor pack finally, it didn't look anything like my Haynes manual but I did figure out that pic posted above and now i have it out. There were a lot of leaves inside there and the resistors look pretty rusty and it has a 3 spade connector and a single spade connected to it, not a nice clean connector like the pictures in the Haynes. Now I just gotta hope I can find a replacement. Thanks. If switching the resistor pack doesn't help would the next step be the dash switch or just getting a new motor?

 

[slim]

It is on ths back of the blower housing. Open the hood and it will be on the right side of the firewall. Has wires going ot it and only 2 screws holding it in the blower housing.

 

[GusDaDog]

how do you like this idea...I just need this thing to work and I can't find a resistor assembly other than LMC for $21 so maybe until I get a new job can I make a jumper from a hot line into the resistor to the line in on the fan motor to have a simple on/off. Just a wire with a 20amp fuse and two male spade connectors to go into the female spades that connect onto the resistor pack?

 

[slim]

You might be able to get away with that. From reading the other posts I dont think that it is just your resistor that is broke. Yes the resistor controls the other speeds, But high is almost no resistance.Might wanna try jumping the blower wires to see if it will come on. Then to get you by until you get another job you could wire it hot and put a on/off switch inline. I hope I made some sense in any of this.

 

[GusDaDog]

yeah...that made sense...I got some interviews next week so hopefully I can fix it right soon but winter in western Michigan over by the lake here doesn't lend itself to many heatless days. Thanks.... (the blower motor can handle 12v alright right if I direct power it off the battery to make sure it works?)

 

[slim]

I am pretty sure it can handle running straight on 12v. I cant find my haynes to look at the wiring diagram. But if you do wire it straight to the battery be sure to put in a fuse or some form of circuit protection inline also. Also I think I paid only 30 bucks for my resistor from Ford last winter. Might wanna give them a call and see what they have to say.

 

[GusDaDog]

LMC is only $21 shipped but I only have like $50 left in the bank after paying December rent and I don't wanna wait 10 days for heat either....

 

[slim]

Well check to see if the fan is coming on at all by putting power to it. If it is then you can rig the switch up pretty cheap to get you by. Also try hitting the fan motor with hammer/screwdriver or somthing when it dosent come on. That might knock the brushes back into contact and run.

 

[GusDaDog]

ok, update...I got to thinking to check everything out with my voltmeter. Ok, for reference I have a 3 spare harness and a single spade that both connect to the resistor assembly. I grounded my voltmeter and tested the hot against battery and it was good. Then I tested all 4 wires with the truck running and the blower on in all speeds and never got a signal....does that mean power isn't even getting TO the assembly? What's next, my switch?

 

[Dustball]

No, I believe it's the other way around. The blower gets a direct 12v feed and the controls/resistor pack switches ground. You're effictively testing ground to ground the way you had it.

 

[GusDaDog]

so if I was to take the black wire of the motor and directly ground it ; it should work on high speed?

update: I just applied a direct 12volts looped from the battery and other than some sparks I didn't hear the motor try and turn at all....was that a good test?

 

[Steve83]

If you ran the 2 wires of the blower motor DIRECTLY (through some jumper wires) to the battery and it didn't spin, then the motor is bad. If either of the motor wires was still connected to the truck's harness, then there's no telling what you did.