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John Kimbrough
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My heater fan is not working and I would rather not tear the dash apart to find out why.  Does anyone have a good way to troubleshoot the fan to see if it is bad??  Jumper it somehow to test its functionality?  Anyone have a diagram of how the fan high/low switching circuit works or pictures of the electrical hookups?  I did not find the electrical schematic helpful.  I may have it hooked up incorrectly.  Any thoughts???  John.

JodyFKerr
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John,

Providing it's still wired originally the wires for the blower motor exit out a small hole in the firewall right next to the heater unit. (left hand side) you should be able to just disconnect it there and run a test lead to it from power.

Jody

dwalls1
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Question on this heater thing. I moved the heater valve from on top the cam cover to the wheel well and am pleased with the aesthetic improvement, but am wondering if the valve will work the same as the flow is reversed from the cam cover mounting position. Am I correct in assuming that the valve is not directional and will still function the same? Thank You, Dale

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Brett Gibson JH5 20497
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You are correct, it's just a vacumn controlled valve, open / close.

JHRV8
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Back to the heater fan motor, if we may, there are two wires exiting the firewall next to the heater core, may I ask are these for low and high speed? I apply 12v to either and there is no response; any explanation will  be greatly appreciated....Bob

JodyFKerr
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In regards to the blower motor, it only runs at one speed, so if you are getting no response to the motor, something's wrong.

I would check the wiring first, and then the brushes inside the unit.

Jody

JodyFKerr
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Oh,and the wires are one circuit. + and -. The blower motor is not a switched unit.

John Kimbrough
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 Thanks for all the comments.  I don't know about others, but my fan is a 2-speed.  There is a resistor that cuts in on the low speed, I believe.   Will have to do some testing.   

Gary Martin JH 15371
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The two wires coming directly from the blower motor should be + and - . Ground one and apply power to the other to test the fan, it should run full speed. Can't remember if the wires are colored, if so ground the black one. If it is hooked backwards it should not hurt, it just will spin backwards. John is correct in that there is a resistor between the fan switch and the motor for the low speed. Gary.

Jon Plowe
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The one speed issue may be that a similar switch has been used as a replacement - you find that style of switch on all sorts of 1970's British stuff but not all were two speed fans -  the height of sophistication in the 1970's! may be that's what's happend in the past

John Kimbrough
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Thanks for all the help.  Now I just need to find a little time to do the troubleshooting.  Have been consumed by working with my daughter on a new deck for her house.  Will get to it before winter, anyway.  John. 



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