Heater Fan Not Working After Blazer Blower Upgrade

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slumley1
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Heater Fan Not Working After Blazer Blower Upgrade

Post by slumley1 » Tue Nov 22, 2011 11:49 am

I have an 85 cj7. I recently pulled out my heater box, cleaned it all up, installed a 73 blazer blower motor, and put it all back together. I plugged it back in to the same brown single wire that came off of it. When I turn it on I get nothing. I checked the 30amp fuse that's in it and that's fine. The switch worked fine before I pulled it out. I know the motor is good.

Where should I start? Please help.

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karlvin08
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Re: Heater Fan Not Working After Blazer Blower Upgrade

Post by karlvin08 » Tue Nov 22, 2011 3:20 pm

If it is just one wire going to the blower, then it needs to be grounded through the housing of the motor. When you had everything apart you may have removed a ground somewhere, or if you reprinted things may have made it so it can't ground. Try scratching a little paint off around one of the mounting bolts and running a wire to the body of the jeep somewhere close by you can scratch a little paint off under a bolt.
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slumley1
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Re: Heater Fan Not Working After Blazer Blower Upgrade

Post by slumley1 » Tue Nov 22, 2011 5:41 pm

I started with hooking up a 12v battery charger. I hooked the positive to the connector that comes off the blower motor and the ground to the chassis. The motor started up. I then hooked a multimeter to the wire and the black probe to the negative pin on the battery. It read 12v when the fan switch was turned on.

I also ran a ground wire from the fans mounting plate to a bolt in the engine bay (the bold that is attached to the heater box that comes through the fire wall. I can't hook it to the body since it's fiberglass. It still didn't work. Is that a bad ground? Could it be something else? I checked the relay that plugged in to the upper plenum and it still "seems" to be plugged in.

What else can I try? I really appreciate the help. It's hard to search and find the right answer since everyone's problem is slightly different.

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karlvin08
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Re: Heater Fan Not Working After Blazer Blower Upgrade

Post by karlvin08 » Tue Nov 22, 2011 6:13 pm

Hmm, you may have let the magic smoke out. It sounds like you are on the right track, I am not sure where to go next without having it in front of me.
Overgunned? Hell, that's better than the alternative.
A big hole lets a lot of air in, and a lot of blood out.
E. Kieth

Reading is Fundamental

My 3 Favorite words..."Your prescriptions ready"
NavinRJohnson wrote:Sorry, but you guys are clueless. Any hair left on the badger interferes with the process, because the bits of the watermelon get caught in the hair. It's a sticky phucking mess. You don't really want to have to deal with that while looking for the quarter.

slumley1
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Re: Heater Fan Not Working After Blazer Blower Upgrade

Post by slumley1 » Tue Nov 22, 2011 7:10 pm

It was a bad ground. When I took the ground wire and put it directly on the negative battery post, it works perfect. Now I just have to find something to ground it to besides the battery.

Yay!!!! Thanks for the help.

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Re: Heater Fan Not Working After Blazer Blower Upgrade

Post by Boodyrider » Tue Nov 22, 2011 11:37 pm

That's the problem with a glass body. ALL grounds must be run to a connection point that in turn is wired directly to the negative terminal of the battery, as the body itself can't be used as a conductive path.
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