Replacing Blower Resistor

[Bill]

I have a 1998 Chevrolet Prizm (same as the Corolla) with air bags,
the blower for my heater & cooling system
will only work on ‘High’, the fan will not
work when I turn the fan speed to a slower speed.
I have a Haynes automotive manual, which instructs me to check and/or replace
the blower resistor that is located on the bottom side of the
passenger dash area for this problem with the heater blower.
The manual gives a warning and instructions to turn the key in the steering column
to ‘Lock’ and then remove the ‘Negative’ cable on the battery and wait at least
2 minutes before servicing the ‘Blower Resistor’, to allow the capacitor to discharge,
also, the manual advises me to see Chapter 12 for more information.
Chapter twelve explains the same procedure but also says to ‘Remove’ the key
after turning to ‘Lock’ in the steering column,
and then to disconnect the ‘Yellow’ connectors (for the Air Bag system)
under the steering column and seats.

Do I have to disconnect the Air Bag ‘Yellow’ connectors also to perform the resistor
check and/or replacement?

Or just turn the key to ‘Lock’ and disconnect the Negative battery cable?
Thank you for your help.

 

[Gary Allan]

The same warning is in the jeep FSM (factory service manual)...it's basically a CYA warning for whenever you tamper with things under the dash.

 

[kenw]

btw, the "resistor" is an open air, extremely high wattage coil of wire that cannot be replaced individually with a part form Radio Shack (or anywhere else on the planet). They are usually located in the airduct to blow air across it.

you will need to replace the entire circuit board. sometimes you can find one intact in a junkyard.

 

[Gary Allan]

That's how it is in my jeep Wrangler. It's a circuit board ...serviceable only by replacement. Mine's around $35 from the dealer.

The older (70s) had more sophisticated resistor networks. You typically had 6 or 7 speed fans back then ....3 vent/ac 3 heat and 1 for recirc ac ..all through different resistors.

 

[Bill]

Thanks for your comments guys,
about the process of setting up the vehicle
to do repair work under the dash, the manual instructions to
'turn the key in the steering column
to ‘Lock’ and then remove the ‘Negative’ cable on the battery and wait at least
2 minutes before servicing', this is the same as turning your key so you can to take the key out of the steering column, correct?

The instructions to 'turn the key in the steering column
to ‘Lock’ and then remove the ‘Negative’ cable on the battery and wait at least
2 minutes before servicing’ seems easy, the part I do not like is undoing the ‘Yellow’ connectors to disengage the Airbag system, the manual gives step by step directions
on how to do this, have you guys done this before, am I making more out of this process
then I should be?


From the looks of the pictures in my manual,
the Resistor is held in place by two screws,
it appears I would take out the screws to remove the Resistor, then screw the New Resistor in place,
there are no comments about replacing a circuit board or the Resistor being part of a circuit board assembly.

 

[kenw]

well, on any toyota I've seen the resistor is in fact a circuit board with several resistors (you need a different one for every fan speed except high). They seem to have about a 10 year life in Toyotas on average.

They may call it "the resistor", but it's probably just semantics. Tech writers are like that, you know....

Regardless, what I'm saying is that it's unlikely you can repair "the resistor" or "the resitor board" or "resistor circuit"; you'll have to replace "the whole thing".

It's a question that seems very popular in Toyota discussions once the "whole thing" is removed and they find out how much the dealer wants for it.

 

[1sttruck]

Our '87 Honda Civic blew the blower resistor, and I replaced it with two ceramic power resistors from Radio Shack, wired in parallel to deliver the resistance. Never had another problem with it.

 

[XS650]

quote:

---

Originally posted by Bill:

From the looks of the pictures in my manual,
the Resistor is held in place by two screws,
it appears I would take out the screws to remove the Resistor, then screw the New Resistor in place,
there are no comments about replacing a circuit board or the Resistor being part of a circuit board assembly.

---

You can check on reality be asking your friendly dealer parts guy how much of the car you have to buy to get the resistor. If you're lucky, the resistor will be available separately.

Unless someone here has experiance with your make and model, anything you hear here is pure speculation. They are done different ways on different cars.