Heater Blower Quit - Help!!

[Ecomike]

No, I'm trying to avoid pulling the motor out unless I absolutely have to.

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Just make a jumper cable wire set, hot wire the motor to the battery. I use a medium set of battery clamps on the battery side, and small alligator clips on the blower motor connector side, and some scrap 12 guage wire.

 

[Pelican]

You can wire the blower motor directly to a current source (battery) without pulling it. Just find a way to attach a wire to one side of the plug and touch the other wire from the battery or other power supply to the other terminal (carefully) When doing this using an automotive battery, it is good practice to include an inline fuse in the circuit.

However, if you are getting no voltage at the plug, the motor certainly is not going to run to start with.

 

[Ecomike]

Update: Noticed today that the center selection switch (AC, head, feet, defrost etc) works. It will redirect air depending on switch position. Temperature control doesn't work. Fan speed doesn't work. I'm thinking the hvac control head is bad.

The temp control just operates a wire cable to a damper door.

On the inline fuse, good idea, 25 amp is the required fuse size.

 

[OnorOffroad]

Ok. I'll give that a try tomorrow. What would cause the plug to have no power going to it? I was also planning on having a look at the ignition, I read somewhere on here that sometimes the wire in the ignition can burn out or go bad.

 

[Ecomike]

Being a 99, there should be a an AC blower fuse and relay in the box under the hood?

 

[OnorOffroad]

The fuse was good. I can replace the relay tomorrow. Is there a correct way to check voltage at the plug going to the fan switch? If so, any idea how many volts should be coming from that plug?

** My HVAC control doesn't use the cable, it's electric.

 

[Ecomike]

The fuse was good. I can replace the relay tomorrow. Is there a correct way to check voltage at the plug going to the fan switch? If so, any idea how many volts should be coming from that plug?

I would connect the meter black probe to the battery negative post, then using volts check for voltage at each harness side contact with the red meter probe. If you have 12 volts, then switch to ohms and test the second harness side contact to verify the second wire is indeed grounded.

 

[nick86]

I am having a similar problem with my blower motor. I accidentally put my battery cables on backwards and fried the alternator. Replaced the alternator and noticed the blower wasn't working anymore. The wipers and radio, windows, lights, etc are all still working.

I checked voltage at the blower motor plug and I'm getting a voltage reading. I'm not an electrical guy, but it was reading 00.5 at the plug on the "200m" setting on my multimeter. I also checked voltage at the resistor and I was reading anywhere from 7 to 1 depending on the position of the switch. So i think the switch is working. The resistor looks good, and all the wires and plugs look good too.

Is it safe to assume the motor itself is bad?

These number don't make sense, as you should be looking for 12 volts with it on Hi. Try tapping on the motor with a small hammer, if it starts working that's a dead giveaway it's the motor

 

[OnorOffroad]

^^ yea I wasn't doing it correctly. I went back to do it again at the blower motor. I haven't checked at the harness side plug to the hvac fan switch or at the resistor yet.

 

[OnorOffroad]

Hot wire tested the blower motor. It works. Tested the harness side plug leads at the fan switch. Had slightly less than 12V on the second to last pin. I think the harness/plug is good. I'm thinking the hvac control unit is bad. Yes?

 

[OnorOffroad]

Another update. Took the hvac control apart and checked continuity of the board. Seems fine. I don't really know what else to check.

 

[OnorOffroad]

Final update: It was the 15amp fuse under the glove. I must have missed it the first time, went back to test all again and noticed it.

Thanks for all the help!

 

[Ecomike]

Final update: It was the 15amp fuse under the glove. I must have missed it the first time, went back to test all again and noticed it.

Thanks for all the help!