I have an '86 Bronco II. The heater fan only runs on the "High" switch
I have taken the switch out and checked for continuity across poles at
each switch position and there is continuity between one pole (common?)
and one other pole in each of the switch positions. From this I assumed
the switch was working and I replaced the fan motor.
It still only runs in the "High" position. (The replacement motor only
had two leads but the parts guy said this was a multi speed motor)
Can anyone help?
I have a '90 Grand Marquis that had the same problem the other day
when the temp went into the teens. Since then the blower now works on
Does my car use the same resistor pack? If so, could you give me an
idea where it is located?
What actually goes in the resistor pack is a thermal fuse in series with the
resistor chain for setting the lower speeds. It's placed on the resistor
pack to prevent a fire hazard from overheat of the resistors if the fan
stalls. They commonly fail in the winter when the fan might be frozen up
from snow or slush enetring via the freash air intake. The circuit is
bypassed in high speed, as there are no resistors in the circuit in that
condition. At least you have the high speed...on my 94 Escort, if the
thermal fuse goes, you lose all blower function, including high speed. I've
had to replace several over the yeasrs in my Escort and 97 Taurus, always
in the winter.
At any rate, the resistor pack is an easy fix, as long as you can get at it.
In my Taurus and Escort, its mounted in the blower discharge ductwork behind
the glove box. Held on with two self tapping hex head screws, and has a
multi-pin connector that connects the wiring from the fan control switch and
feeds the fan motor its voltage.
The resistor packs run about 10 to 12 bucks at Ford parts departments. If
I knew what rating the thermal fuse was, I would just replace it. The
resistors themselves ususally do not fail. Radio Shack used to stock
thermal fuses, and I'm sure you can get them from applicance repair shops
for not more than one or two bucks. They are also used in things like
coffee makers. In a pinch, you could jumper around the thermal fuse until
you can get a proper replacement unit. But be careful to ensure that the
fan does not stall out!
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