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Discussion Starter · #1 ·
HellIo all,
I have had this shadow 1 1975 for ten years and love it to bits ! I have done a lot of work on it and have eventually solved all the problems that have arisen, but now I am at my wits end with this one.
The car allways had just one blower speed. the 3rd and fasted speed. That was fine as it heated up really well an quickly.Now the blower wont work on any speed.
I checked the fuse, all ok and power going through it. I dismanteled the centre consul and removed the blower speed unit. ther are 4 wires and no power to them.. I checked the 3 resistors at the front left of the engine and the wires seem tight.Only thing I can think of was that I changed the speedo cable a voule of days before...........did I move a connection ?? Or am I missing something obvious here ? any help would be greatly appriciated.
Many thanks for your help.
Guzzi Frank
 

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Check the blower motor with an external 12 volt source to take that off the table, when it comes to electrical problems, never assume anything.
I suspect the resistors are open; with the switch on, one of the resistors should have 12 volts on one side, check them one by one moving the switch position and check all of them.
If they all have 12 volts, you can then confirm with a continuity test that in fact the resistors are all open.
If there is not 12 volts on either side, then suspect the switch.

You may eventually need a wiring diagram to trace down where the possible open circuit is.
The switch may also be faulty as well _ check for continuity in its different positions.

How did you check the fuse, if just a visual check, that's not good enough, replace with a known working fuse ?
With the fuse removed, one side of the fuse's terminals should have 12 volts, make sure it does.
 

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Discussion Starter · #4 ·
Thank you Jim, I will start with the fuse, then the motors and then the resisters. Did I dismantle all the center consul for nothing.probably ! but its all good practice. will let you know how it goes. Thanks again. Frank
 

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Discussion Starter · #5 ·
Well, I am stumped. I am not good with electrics but I try my best..............Changed fuse , live at both ends of the contacts. Cleaned the contacts on the resistors with a small wire brush. With the blower switch in any position I have NO current to any of the resistors. both contacts on the resitors register nothing on my test lamp. The switch has 4 wires , all yellow going into it. there is no power in any of them at any position. should there not be power going to the switch ? and why do I get no light on my test lamp on the resistores? Can i by pass the switch to get at least one speed ? forgot to mention that power to the blowers from a separate source has them working fine. I repeat that i am not good with electrics....I set a car on fire once, but thats another story. What am I missing ? Should have another switch in a couple of days. Last thing, the blower has only worked on the high speed for the last ten years I have owened the car. Any ideas very welcome !!

Many thanks for any help. Frank
many thanks. Fra
 

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Ok then if the fuse is good and making good contact with the fuse clips and no power at switch then the fan relay is not working. Go to the Bentley Heritage site, download TSD 2476, and scroll down to wiring diagrams which will be at the very end of the document. Locate the fan relay. In TSD 2476 there will be a location diagram, read through the electrical section to find it. You can replace it with the same type or wire in a standard Bosch cube relay. You can also bypass the relay temporarily for testing purposes. You may find the fan speed switch is faulty due to corroded contacts but they can be carefully cleaned.
 
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