R107 blower motor

pablo diablo

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Hi Can any one please tell me why my blower motor is running on full speed with the switch off
I have a 79 450 SLC with air con
With the air con off and the blower switch off the fan is running on what i think is full speed the only way to stop is pull the fuse
 

mikestrivens

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Sounds like the regulator has failed.
 

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It must be a wire grounding that should not, the fan reg is wire wound,,unless the reg has a short
 
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pablo diablo

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Hi thanks for the reply where is the regulator located, i did notice the other day it seemed to be on low all the time then this stopped and now it is running flat out
 

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This one gets hot as wire wound,,,on the bulk head possibly

Yes with an ohmmeter but you need to know the values, but a short would be easy to test
 
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pablo diablo

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if i beat the car with a big stick will that cure it, i have saved this car from going to the scrap yard with the rest of the SLCs but i think it wants to go its a battle of wills at the moment
 

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I would think that one of the resistor is shorting ground, it may respond to a bashing with a big stick ;)
 

Multi-Tech

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The resister/regulator is on the bulkhead next to the heater motor.
It's a common problem if its not a ground issue it will be down to the points inside which get stuck, you can sometimes free them off my dad had the same with his SLC. (Also lives in Shepperton so may pass each other one day)
 

Benzworx

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Regulator is located rear of engine/ bulkhead large plastic cover, and you can see it inside located near drivers side it has a plug connected to it
 
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pablo diablo

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hi yes it was the points that were closed do you know what the function of the points are, i have temporary widened the gap to stop the fan running.
The points on a wiring diagram look as if the should be normally open but mine were closed be nice to understand their purpose
 

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What were the points mounted on
 
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pablo diablo

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hi they are in the regulator i cant understand what they do not sure if they are like a thermostat type operation but why
They are fed by a live straight from the fuse and if contacts are closed straight onto the fan
 

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If they are only a pair of points and not joined to anything, then they could be a thermal device
 


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