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Discussion Starter #1
Hello; This is my first time here but I'm stumped. Blower motor would work then quit, seemed to have a mind of its own. Then it quit completely. Now I have no power from to the front blower motor switch. The rear is separate and works just fine. I have replaced the switch, resistor, and motor already. I have also checked the fuse in the PDC Block and its fine. I removed the relay and tested it across the battery to make sure it clicks. I know I have power at the fuse and on two terminals of the relay but no power at the switch. ( The resistor I changed is on the firewall behind the right side front strut.) I have also disconnected the main computer for a short time then reconnected it and there was no change. I was trying a system reset hoping it would solve my problem. Help!!
 

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For troubleshooting just about any accessory system problem the relay is a good place to start because it's easy to get to and it will quickly eliminate large parts of the circuit. You determine if the control side and the output side of the relay are working. A fault anywhere in the system will show up while testing those two functions.

Easiest thing to start with is bypassing the output contacts. Turn the blower switch to high to set the ground to the motor, remove the relay then with the keys in your pocket jumper contacts 30 and 87 on the relay socket. The blower should spin immediately. If it does the output side of the relay is working. You've just eliminated half the system as the culprit. The switch is providing the ground to the motor via the resistor block and the battery bus is supplying power via the fuse in the PDC. If the motor doesn't spin check for a ground at pin 2 (black wire) at the motor connector and power at pin 1. One or the other is missing.

" I know I have power at the fuse and on two terminals of the relay but no power at the switch." The switch supplies the ground not the power to the blower motor.

If you would like the wiring diagrams send me a private message and include an email address.
 

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Discussion Starter #3
no power @ front blower motor

When i posted the last time i had no power to the front blower motor. Now i have power coming into the motor and when i check the wires i have 12v on one wire and continuity on the other (ground). I have used two different switches and as i said before, replaced the motor and resistor. Now i have also changed the PDC and still cannot get the motor to work even jumping across the 30 & 87 terminals of the PDC relay. Not sure what to do next. I did also fasten the resistor so that i is not flopping around. HELP.
 

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Hmm. This is starting to sound like something out of the Twilight Zone. If you have power and ground at the blower motor connector it should spin. Did you install a bad motor? Measuring resistance across the two motor contacts you should get some resistance, probably several hundred ohms. If you get infinite resistance then the motor windings are open.

You've changed everything in the system but the relay. The relay can be swapped with another on the panel. Just to clarify, when you say "switch" you mean the blower speed switch on the control panel meaning you've changed the entire HAVC control panel right?
 

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Discussion Starter #5
no power @ front blower motor

I'm back! This time I have good news. The blower motor works. We have heat again. I hooked up a second motor without putting up into place and the motor worked without any problems however every time I would put it up into place it wouldn't work. I finally went to the hardware store and picked up a can of electric motor cleaner. I spayed some in around the brushes and the ends of the motor shaft. Then I spun the motor by hand several times until it would spin freely. Next I used an air compressor and blew it all out, wiped it off and hooked it up while holding it. Turned it on and it worked just fine. I tested it this way 10 times before putting it into the housing. Once there I tested it after I put in each holding screw until it was completely installed. I went out just a few minutes ago and started the van and the motor kicked in instantly. Thanks for all your help. (Oh yes! I also cut out and replace the blower motor plug.)
 

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Thanks for posting your fix. These exchanges can help a lot of people. It seems unusual that the new motor you said you originally replaced would have had those impairments. Perhaps it was a used motor? In any event, it's great you worked through your problem and have heat back in the cabin.
 
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