I have a 98 chev diesel 1/2 ton, and my heater fan was only working on high, I replaced the blower motor resistor and now it works on all speeds but the resistor starts to smoke on the two slower speeds the two faster speeds seem fine. Why does it do that and what can I do?

Its faulty blower motor resistor. The low and medium speed on blower motor is controlled by resistor and its actual speed is high. So because resistor is not working, blower motors actual speed which is high is working.

It can be faulty blower motor or faulty blower motor resistor. Get the blower motor inspected. If it's faulty it has to be replaced.

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For blower motor testing and replacing, check the link below: ----

Blower motor Testing/replacing for all vehicles?

http://repairhelpcenter.blogspot.in/2012/02/blower-motor-replacing-for-all-vehicles.html

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These will help.

Thanks.

Its under dash panel.

HEATER BLOWER MOTOR

Its faulty blower motor resistor. The low and medium speed on blower motor is controlled by resistor and its actual speed is high. So because resistor is not working, blower motors actual speed which is high is working.

It can be faulty blower motor or faulty blower motor resistor. Get the blower motor inspected. If it's faulty it has to be replaced.

=======

For blower motor testing and replacing, check the link below: ----

Blower motor Testing/replacing for all vehicles?

http://repairhelpcenter.blogspot.in/2012/02/blower-motor-replacing-for-all-vehicles.html

------------

These will help.

Thanks.

I would replace the blower motor resistor first then see if that corrects this. The resistor is located next to the blower motor under the dash.

This condition is caused by a defective blower motor speed control resistor. The resistor is located right next to the blower motor with the connector end sticking out of the ducting for the AC/Heater system. Very easy to replace and the part is cheap as well.

Hello,
You may want to try your fan on all speeds. If it will work on high, you have a bad resistor for the fan motor. ( high speed doesn't go through the resistor ).
If it doesn't work on any speed, I would check the following;
1. Make sure the fuse isn't blown for the fan blower motor.
2. Check, or have checked the wires between the fan control switch and the fan blower motor.
3. Have the fan control switch checked.
4. Have the fan blower motor checked.

I hope this helps you.

The blower fan only working on high is caused by only one thing, that is a defective blower motor speed control resistor, the resistor is located next to the blower motor in the air ducting, replace it and the problem is solved.

It sounds like the blower motor resistor is going bad. It's located near the blower motor. I would also check the connector going to the blower motor resistor.

Hi!!
The Blower Motor Resistor also called Manual Temp. Control resistor), is fried, replace. The price with floor console $25 and without floor console $65. here is a pic.


the resistor is located on the blower motor housing, fastened by two screws. It is the part where the electrical plug connects, the plug on the pic. goes to the blower motor.
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most likely ur multi-switch[fan selector switch] test out put for the other speeds if no output replace switch if good test motor