View single post by Jay T
 Posted: 02-21-2006 07:03 am
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Jay T

 

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 As some of you already know, the two speed fan switch is dependent on a resister attached to the driver side of the blower housing.  The high speed fan setting is accomplished by allowing a full 12 volts to reach ground via the fan switch and the low speed is a result of a reduced voltage due to the resistor.

My low speed doesn't work.  I checked the wires and determined the problem is the resistor.  After removing it, I found one of the connections to be a little loose.  I was able to make a solid connection with a tap from a hammer on a screwdriver on the rivet holding the connector.  Next I checked the resistence and came up with around 3.3 on a scale of 200 ohms on my digital volt-ohm meter. This included the low speed wire from the resistor to the switch, green/yellow.

Question: does anyone know what the resistance should be?

Note: in my car ('74 JH5), the high speed (or full speed) wire color is green/slate and the low speed wire color is green/yellow.  This is the reverse of what is specified in the very nice wiring diagram I downloaded from this site.  The diagram has been of great help to me.