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Discussion Starter #1
my blower doesn't work properly. It only works on one setting, high, but that doesn't seem very high. This is my first bronco. Is the blower moter shot? I replaced the blower switch, but the same issue continues. What about the blower resistor. I don't even know exacly what that does. Napa sells the blower moter resitor wiring plug, but not he resistor it self. Anyone have any insight?
 

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I had this exact same problem not a week ago. I had to replace my motor (I think the motor caused my resistor to go bad, I only had high, then lost it all entirely...$22 at AutoZone) and I replaced the fuse ($1) and I replaced the resistor pack(which was very hard to find new. I got mine eventually from a Ford Dealer for $17) so $50 and an hour later I am fine.....good luck, it's not hard once you have the parts.....

P.S. you probably ONLY need the resistor, just mentioned the motor because that was MY problem
 

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Yeeeeehaw Y'all!
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Now that is just a great friggin pic...... :thumbup

I've got the same problem on my 88, (only blows on hi), but since it blows, it's been a little low down on the priority fix list. But now that I know what it probably is and where to look for the problem, I'm going to fix it.

Thanks Steve......

Steve83 said:
Yes, it's the resistor. It's in the engine bay between the accumulator and the blower motor. If you can't find one locally, I think I have one in the junkpile.

 

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Who needs oil anyways....
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Depending on the year, it might be prone to collecting leaves in the ductwork. Check there. They would all start piling up at the bottom which you can easily access if you remove the front plastic wheel well. Cleaning just the passenger side on my 86 made a world of difference. There was also crap in the ductwork near the heater core.
 

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Discussion Starter #5
Thanks Steve,

I finally hit the junkyard and picked a new Resistor for $1. Blower works great now.

Next Step A/C.

Anyone do a recharge?
 

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Charlie don't surf..
'92 Ford Bronco XLT
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15,186 Posts
dusting off an old thread..got in my rig this afternoon, it was raining so after starting it up I switched to defrost..fan was on the low setting but the blower motor was going like I had it turned on high..same on every setting..I'm assuming it has to be the blower motor resistor..funny thing is I just replace one in my Crown Vic a couple of weeks ago..
 

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Charlie don't surf..
'92 Ford Bronco XLT
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15,186 Posts
Picked up a new blower resistor from NAPA today and expected that would cure the problem..got it installed and turned the vent on, same thing..fan is blowing on high all of the time..now I guess it's possible the resistor I got from NAPA was bad but I'm thinking the problem lies elsewhere..any other thoughts?
 

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Does the blower still run at full speed with the resistor assembly removed? If so, you probably have a short on the motor ground side. Either between the resistor pack and the blower motor, or at the blower motor switch.
Pull the connector off the resistor pack and check.

Below is the EVTM schematic for a '94 if you think the wiring colors/connectors are close enough.



http://www.supermotors.net/registry/media/909464_1
 

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Charlie don't surf..
'92 Ford Bronco XLT
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don't know..I'll check it tomorrow..this is exactly what I was looking for, couldn't seem to find it in my Haynes..thanks.:thumbup
 

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Picked up a new blower resistor from NAPA today and expected that would cure the problem..got it installed and turned the vent on, same thing..fan is blowing on high all of the time..now I guess it's possible the resistor I got from NAPA was bad but I'm thinking the problem lies elsewhere..any other thoughts?
Hey ! I'm just a the retard that works at the local...wait, make that multi-national... auto parts store:banghead. But I'll tend to agree with Mikey on this one. It sounds to me like the blower switch itself may be the problem .
 

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yo,
Check continuity of blower switch.
TEST PROCEDURE
Switch Position.....Continuity Between Terminals
Low...........B
Medium 1.....B + D
Medium 2....B + C + D
High..........B + A + C
Is switch continuous in all positions?
Yes - SERVICE Circuit 57 (BK) between switch and ground.
REPAIR as necessary. G201 is Behind bottom of LH cowl panel (driver's side kick panel); Components Served (through Splices, etc.), Blower, Compass/Outside Temperature Module, Day/Night Mirror, Inside Cargo Lamp, Left Power Lumbar Compressor Motor, Outside Cargo/High Mount Stop Lamps, Right Power Lumbar Compressor Motor, Seat Belt Switch, Door Lock Actuator (PDL & Probably Power Window Motor);
G201 Location pic in a 92 Source: by BeastBronk at http://i69.photobucket.com/albums/i42/jprix82/GEDC0025.jpg
..
No - REPLACE heater blower motor switch.
=======
 

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Charlie don't surf..
'92 Ford Bronco XLT
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15,186 Posts
great info. Thanks again guys..I'm betting on it being the ground wire, but will start testing over the weekend.

To clarify, the ground that services the switch is behind the kick panel on the drivers side..

No, the "fan only works on high" description means all fan switch positions are dead, except high, which works as it should. That's invariably caused by the thermal fuse in the resistor burning open, leaving the only working circuit the one that bypasses the resistors & puts full power to the motor.

Your symptom is "all switch positions cause high fan speed", which suggests the fan switch has failed internally, or the wiring between it & the resistor is shorted. Unplug the resistor and test continuity from each pin to each other. With the switch in LOW, all should be open (infinite resistance). If not, pull the fan control out of the dash to inspect the switch & retest the wiring with both ends unplugged.
yo,
Check continuity of blower switch.
TEST PROCEDURE
Switch Position.....Continuity Between Terminals
Low...........B
Medium 1.....B + D
Medium 2....B + C + D
High..........B + A + C
Is switch continuous in all positions?
Yes - SERVICE Circuit 57 (BK) between switch and ground.
REPAIR as necessary. G201 is Behind bottom of LH cowl panel (driver's side kick panel); Components Served (through Splices, etc.), Blower, Compass/Outside Temperature Module, Day/Night Mirror, Inside Cargo Lamp, Left Power Lumbar Compressor Motor, Outside Cargo/High Mount Stop Lamps, Right Power Lumbar Compressor Motor, Seat Belt Switch, Door Lock Actuator (PDL & Probably Power Window Motor);
G201 Location pic in a 92 Source: by BeastBronk at http://i69.photobucket.com/albums/i42/jprix82/GEDC0025.jpg
..
No - REPLACE heater blower motor switch.
=======
 

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Charlie don't surf..
'92 Ford Bronco XLT
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15,186 Posts
ok, so the wire(s) I'm looking for run from the switch to the resistor, is that correct? Any idea where they come through the firewall?
 

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1,715 Posts
Would a "old and tired" resistor cause the fan speeds not to be as powerful as they were when new? Or do they either work/don't?? On a 1990 if it matters.

thanks
tim
 

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Charlie don't surf..
'92 Ford Bronco XLT
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15,186 Posts
Would a "old and tired" resistor cause the fan speeds not to be as powerful as they were when new? Or do they either work/don't?? On a 1990 if it matters.

thanks
tim
The resistor either works or doesn't, your symptoms probably indicate your fan motor is crapping out..
 

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1,715 Posts
That is what I figured. Although "crapping out" is probably too harsh a term for it. It really is more like just not as strong as it used to be. Of course with a bad shoulder I can certainly relate. lol

thanks
tim
 

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Charlie don't surf..
'92 Ford Bronco XLT
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15,186 Posts
ok, pulled the connector off the resistor and the fan still run in high on all settings. pulled the control panel out and all the wires to the switch check for continuity. I couldn't get any resistance measurement from the switch itself. It didn't read at all, so it looks like the switch is the culprit..what do you guys think?
 

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What Steve83 says, the more precise the better.
If I interpret what you said correctly, all the terminals of the switch are connected regardless of the switch position? ("couldn't get any resistance measurement from the switch itself") If that's the case, the switch is indeed bad.
To verify that the switch is bad: Leave the Blower motor switch disconnected, connect the resistor connector, turn the ignition on (Run), and the motor should run at "Lo" speed. The blower motor switch, when disconnected, is the same as the "Lo" position of the switch.

Or try this:
Remove the resistor connector plug, ignition off, remove the blower motor switch plug, measure the resistance (Ohms) from the O/BK (orange w/black stripe) on the harness side of the connector on the blower motor switch to ground (some unpainted part, bolt head, etc.) If you have a ground there (0 or really low Ohms), then the wiring from the motor to the switch or the wiring from the motor to the resistor pack is shorted to ground, causing the motor to run at full speed.
If you do not have 0 Ohms, then do this:
On the blower motor switch itself; remove the connector plug to the blower motor switch, move the switch knob to the "Lo" position, meter the resistance from the connector on the switch where the O/Bk wire connects to the connector where the plain black wire would connect. It should be infinite resistance from the O/Bk connector to all the other connectors on the switch. If you get a reading above infinite on any of the switch terminals, with the switch in the "Lo" position, the switch is shorted.

I personally like to use an analog meter for measuring resistance in cases like this.
 

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Charlie don't surf..
'92 Ford Bronco XLT
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15,186 Posts
with the blower motor resistor connected and the switch disconnected, the switch connector wires showed continuity to each other

What does that mean: they show continuity to each other, or each wire ONLY shows continuity from one end to its other end?You're saying no switch terminals showed continuity to any other terminal with the switch in any position? If you only checked with the switch in LOW, that's the logical equivalent of OFF for that particular switch.

Wiring diagnosis is difficult when you have your hands on it - over the internet, you have to be VERY specific & descriptive for us to unnerstan what you're doing.
 

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Charlie don't surf..
'92 Ford Bronco XLT
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15,186 Posts
Just checked with the switch disconnected and the blower motor is still running at high..:scratchhe..I'm going to re-check resistance of the switch with it disconnected.

What Steve83 says, the more precise the better.
If I interpret what you said correctly, all the terminals of the switch are connected regardless of the switch position? ("couldn't get any resistance measurement from the switch itself") If that's the case, the switch is indeed bad.
To verify that the switch is bad: Leave the Blower motor switch disconnected, connect the resistor connector, turn the ignition on (Run), and the motor should run at "Lo" speed. The blower motor switch, when disconnected, is the same as the "Lo" position of the switch.
 
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