The haeter a/c fan moter only works on high.

The main reason for a resistor to go bad is because the blower is pulling too many amps to work. Check your blower motor.

You have a relay there are 2 speeds low speed and high speed this is controled by a cooling fan module if you changed fan and it does not work then you will need to check the fan module, first the relay its in the engine fuse junction box High speed is marked on the relay C1056 and low marked C1058, here is what you can do go to the high spped relay open thhe cover and expose the relay with key on collapse the relay does the fan come on? if it doesnt replace the fan module if it does you will still have to replace the fan module here is the location is at the radiator on the front (may be under shroud)

Hi, please check the HIGH BLOWER fuse in the car first. If the fuse is good, the problem is likely with the resistor assembly, because the High setting relay is a part of that assembly. The resistor is mounted on the heater box under the dash and has several wires coming out of it. There is also a separate cable on the assembly, I believe for the High setting. You could verify the relay is bad by pulling the resistor out, reconnecting the cables and checking to see if the relay clicks when the key is on and the switch to changed to high. When the relay closes, it connects the 2 terminals in that extra cable to put the motor on high. Please let me know if you have any questions and thanks for using FixYa.

Hi anubus33
If the blower moter is working on low speed only and it's not making any strange noises,there are 3
components that can cause this problem. First and the most common is the blower moter resistor,
located under the hood at the center of the firewall, next is the high blower relay(not uncommon)
located in the junction box between the right strut tower and the firewall and the fan switch on the
dash. An easy way out is to stop by the local salvage yard and p.u. a resistor+relay for cheap they
should be the same as many other GM'S of the same year. The counter guy at the yard will know.
Hope this helps.

Hello leebarker
The blower moter switch or the blower moter controler can cause this
problem. Remove the plug from the switch, use a 12v test light to locate
the 12v power wire in the plug. Next with a small jumper wire bring power from the 12v contact to the low and medium speed contacts on
the plug if the blower changes speed replace the switch if it still only
has high replace the controler. The blower controler is located on the
passenger side end of the heat-a/c box near the blower moter.
By the way the key must be in the on position for this test.
I hope this helps. Good luck.

the high blower relay controls the high blower only
you need a new blower motor switch you control on the dash

First lets deal with front blower. If all fuses checked, there should be a resistor block (which when it goes usually leaves you with high fan only) for fan located on firewall, under the hood on passenger side behind the front strut mount area. It measures 1-1/2" x 3" approx, and will have a wire connector on it. It usually pulls out, with a bit of a fight. Disconnect your battery neg(-) just to be safe before you do. Replace it, that should cure front blower problem. (about $20 at autoparts store) Ask them for "blower motor resistor pack) very common item so they should know what your talking about.

There is a fuse I would check first if you haven't tried that yet. They had problems with the switches in some of those vehicles. If you could take the control out and unpug then reattach the plug it may start working meaning the switch is bad.
You may have a bad fan motor. Do you have a test light to check for voltage at the motor itself?
Lastly, there is a resistor set that changes from low to high that may have one or more resistors burned out.
Dale

it could be the wire behind the fuse panel itself or the plug that plugs into the fan check these with a 12 volt tester and you should be able to find the problem also check the fuses under the hood and if you have an owners manual check in there and see if any are listed and where they are located