Fan Blower Help new motor wont run

[Cesar Diaz]

Hey Guys need some help,

I was having issues with the fan blower squealing while it was running so I bought a new fan at Autozone and installed it with no problems.

The issue I am having is that the fan will not turn on. When I flip the fan speed switch on my panel, I only hear a click and thats it. the fan does not run. I took the fan off connected it straight to the battery and it runs on high without hesitation.

I know there is a resistor as well as a relay, can anyone give me an idea of what the problem could be.

I've located the relay, I will have to remove the shroud under the pass side to get to the resistor if that is the problem.

PS I have factory A/c and Heat

Thanks

[71CHEVYSHORTBED402]

Originally Posted by Cesar Diaz

Hey Guys need some help,

I was having issues with the fan blower squealing while it was running so I bought a new fan at Autozone and installed it with no problems.

The issue I am having is that the fan will not turn on. When I flip the fan speed switch on my panel, I only hear a click and thats it. the fan does not run. I took the fan off connected it straight to the battery and it runs on high without hesitation.

I know there is a resistor as well as a relay, can anyone give me an idea of what the problem could be.

I've located the relay, I will have to remove the shroud under the pass side to get to the resistor if that is the problem.

PS I have factory A/c and Heat

Thanks

I wonder if a connector came loose, since it worked beforehand, such as at the fan switch plug? That's a common occurrence.

The info. below may come in handy for you. Seems it would be wired like my 71 AC, though I did get rid of the anti-dieseling relay, for what worth.

[Sheepdip]

Originally Posted by Cesar Diaz

Hey Guys need some help,

I was having issues with the fan blower squealing while it was running so I bought a new fan at Autozone and installed it with no problems.

The issue I am having is that the fan will not turn on. When I flip the fan speed switch on my panel, I only hear a click and thats it. the fan does not run. I took the fan off connected it straight to the battery and it runs on high without hesitation.

I know there is a resistor as well as a relay, can anyone give me an idea of what the problem could be.

I've located the relay, I will have to remove the shroud under the pass side to get to the resistor if that is the problem.

PS I have factory A/c and Heat

Thanks

I had the same problem when I did mine. Turned out the squirrel cage was a tad long and hitting when installed. Ground a little off and works perfect.

[HO455]

With the fan reinstalled try running a wire from the negative post on the battery to an unpainted spot on the fan body. If it works then you have a bad ground.

This thread should help you.


http://67-72chevytrucks.com/vboard/s...d.php?t=813743

[Cesar Diaz]

Thanks everyone I tried all those things and its not it. I realized it was the wrong motor that was for heater only so I got a new one and it does the same thing. I'm guessing its the resistor because when I turn the switch on I do hear the relay kick on. Im guessing the old motor was straining and overheated the resistor.

Ill let you know what I figure out.

[Rust_never_sleeps]

If the resistor is bad, it should still work on high. Resistor limits voltage to the motor for low and medium, but won't be in circuit for high speed

[dmjlambert]

The basics I suggest start with are:
1. Check fuses. I recommend use a multimeter and check for 12V on both sides of each fuse. Connect neg lead on a good clean ground and pos lead on the fuse clips, not on the fuse itself.
2. Check this short wire is providing a very good ground and the metal under the terminals is scratched bare metal. The wire going straight down from that bolt on the fan is the ground wire for the relay in the cab, and it may be attached on a different bolt on your truck. On the fan is where I decided to connect it on my truck.

3. You're hearing that clicking only when high speed is selected, is that right? The switch is all the way down when it is on high. If clicking only on high speed then that may indicate your high speed blower relay is at least coming on. On high speed, the 12 gauge Orange wire that is plugged into the CIG position on your fuse panel goes to the relay, and comes out of the relay on the 12 gauge Purple wire that goes to the blower motor. So make sure that Orange wire is in good condition and plugged into the fuse panel.
4. Check that the motor runs when it is not installed and out in the open, by using something like alligator clip test wires to connect it to the battery. Note the wires will get hot unless they are pretty heavy duty. If they are light duty you can clip onto the case and other end on neg battery terminal, and another wire clip onto the pos battery terminal and just touch it to the power terminal of the motor briefly. Wear gloves. You can also use jumper cables if you're careful where you touch them. Test that the motor runs at all under power. This is a test with the motor out of the truck because of what Sheepdip mentions, there could be something binding and stopping the motor from getting started spinning. You need to know if you have a bad motor or something wrong with wiring.

5. On these trucks it is common for the connector that goes on the back of the fan speed switch to go bad and melt. Check the condition of the wiring, and look very critically at that connector. Make sure all the terminals are engaged fully into the plastic connector.
Please let us know what you figure out, and if you run into any questions.

[Wrenchbender Ret]

Have you tested the motor installed with a jumper wire? If it runs then it will prove the motor & ground are ok. When you hear the relay click it does not necessarily mean it is good. The armature can pull in but the contacts may not make contact.
Get a test light & a schematic & start tracing wires. The relay is basically for high blower only but I believe it has to be good for the other speeds that go through the resister to work. The relay &/or the resister are generally the cause of this problem.
Check the fuse first with the test light. Often they don't look burned out but can be on the ends from excess heat. Also the fuse holder can be burnt.

George

[Cesar Diaz]

thanks George I did test the motor with direct contact to battery and it runs. same with the last motor which had been sold to me in error, it was for a heat only system, I have AC. I guess I need to figure out how to test the resistor and the relay. I went ahead and ordered a resistor because I read that they can overheat and get damaged from a bad blower motor. I'm guessing that a sluggish fan motor would maybe create higher voltage which could damage the resistor. I also read that a bad resistor can sometimes not allow the fan to turn on at all. Classic industries had a resistor for $16.00 and the one on the truck is 51 years old so no harm in changing it anyways.

[Cesar Diaz]

Hey wrench bender, thank you for a great response.

I will respond to each item by its number to make my reply easy to follow

1> Fuses are good I tested and the clips are good.
2> Ground wire is solid and I did scratch the metal bare, if I run a wire directly to battery motor runs on high.

3> The Relay clicks when I switch to low, I hear no additional clicks when I switch to med or high. All wiring is in good condition and everything was working fine with the old motor (besides the fact that it made horrible noise, it still blew air)

4> Motor is not binding, I tested it outside of installation, and installed direct to battery and it runs fine. High speed only of course!

5> I checked the connector on the back of the switch and it ad the wires are fine.

is it possible that it is a bad switch, even though it activates the relay?

Thanks everyone for the responses, I'm baffled, but I will figure it out!

[HO455]

Just for my clarification. The blower does not work in any speed correct?

If that is true then the problem is most likely in the orange wire between the relay under the glove box and the blower motor. There are 2 sources of 12v positive to the blower they meet at the relay and the relay routes the power to the blower depending on what the fan switch tells it what to do. If the relay is clicking the it is getting a signal from the switch.

Personally I would inspect the connector plug at the blower to start as I have seen several of them fail internally in the past. Make sure the terminal inside the makes a good electrical connection with the spade terminal on the blower.

[Wrenchbender Ret]

It seems strange that the old one worked & now the new one won't without changing anything else.
Check the terminal inside the rubber connector on the orange wire at the end wear it connects to the motor. I have seen them pushed back into the rubber & not make contact with the term on the motor.

George

[Cesar Diaz]

Thanks everyone, I partially solved the problem the motor now works but only on low and medium speed. I had installed it of center by just a fraction and it was enough to bind it. When i was testing it to direct current just holding it into the opening it worked so I didn't think the wheel was binding. When I reinstalled it it didn't work while hooked directly to 12 v. That's when I realized that the fan was off center.

I know have to test the switch to see if it has gone bad or if it is the relay that is not activating on high! Arggggggggggg


PS: Im also getting a vibration on the low and medium speed but it does not do it if I pull the fan out and run it on high with the squirel cage on, feeding straight off the battery. I think the new motor has a bad bearing.

[dmjlambert]

For high speed only problem check the 12 gauge Orange wire that is supposed to be plugged into the CIG position on your fuse panel is making good contact, and check the relay. It concerned me when you said you heard a click only on low fan speed position, the relay should click only when going into and out of the high speed position. So it may be you have a bad relay. I don't know what the click would be from for the low speed position.

[Cesar Diaz]

Hey everyone thanks again for all the advice finally got it all working.

Had to disassemble and clean switch it was filthy inside but i cleaned it all up reassembled the switch and all speeds now work!

You guys are amazing!

[HO455]

Congratulations on a job well done! And thanks for posting your findings I'm sure it will help others down the road.

[Cesar Diaz]

Thanks, i really dont know what i would do without this forum ! Its amazing and so are most of the folks on here.