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Discussion Starter · #1 ·
my technician tells me that he needs 3 hours of time to be able to have the new alternator communicate with the red warning light on the dashboard.......the red light would be on when the alternator malfunctions. He has been using a electric meter .....applying it to the many wires coming out of the rear of the ignition switch.....to try to find the proper connection to find the circuit for that feedback loop. I have been driving the car locally and my tech tells me that my alternator is not charging my battery and I will break down soon. I have a Noco if that happens.
I asked the tech to connect the alternator so it works properly and forego or do not repair the car so that the red light comes on for an alternator malfunction.......is this possible......is there a diagram for electrical connections for the alternator in a 1975 Silver Shadow.?
 

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Again, the workshop manual has the diagrams. It is clear to follow. Hrs to fiddle with the alternator.............your being hosed.Keep him away from the ignition switch unless you enjoy more issues at your expense.
 

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Hi Marc

Fitting a non-standard alternator with an internal regulator is really simple. I have fitted one on my 74 Shadow - a 7127.

Disconnect all the wires from the original regulator, which is situated on the firewall.

The main output of the new alternator connects to the original connector - the thick round one with the nut.

The new alternator will have two control wires - one goes to the wire that was connected to the WL connector on the old regulator.

The other wire is for voltage reference and is best run to the positive on the starter relay.

That's all there is to it. As Wraithman says - keep well away from the ignition switch.

Your alternator may have different control lines so check the installation instructions that come with it. The main point to take away from all this is you connect to the generator warning light through the original wire that went to WL on the old regulator, not the switchbox.
 

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Watch this video through to completion as I messed up a couple of times before I got it right.

 

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Discussion Starter · #5 ·
thank you.....I have an idea that this fine young fella and expert mechanic has no experience with RR vehicles.....and he has become fixated on making the red alternator light work......rather then a routine alternator replacement.
Hi Marc

Fitting a non-standard alternator with an internal regulator is really simple. I have fitted one on my 74 Shadow - a 7127.

Disconnect all the wires from the original regulator, which is situated on the firewall.

The main output of the new alternator connects to the original connector - the thick round one with the nut.

The new alternator will have two control wires - one goes to the wire that was connected to the WL connector on the old regulator.

The other wire is for voltage reference and is best run to the positive on the starter relay.

That's all there is to it. As Wraithman says - keep well away from the ignition switch.

Your alternator may have different control lines so check the installation instructions that come with it. The main point to take away from all this is you connect to the generator warning light through the original wire that went to WL on the old regulator, not the switchbox.
OK.....very good info....I hope this is solved soon
 

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He DOES know there is a separate voltage regulator for the alternator, doesn't he? The red light is controlled by the regulator. Has he just installed a new alternator but can't get it to work?
 

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Discussion Starter · #9 ·
that is correct......he cannot get the red gen light to work......I sent him a message to watch the video ...." " bringing a dead rolls-royce back to life-part 15". ......I have switched to a different Tech.....he has 25 years RR experience.....I bet he can solve my problem,,
 

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Hi Marc

Could you confirm whether the alternator is a reconditioned CAV original or a substitute modern alternator. When you said your tech was trying to get "the new alternator communicate with the red warning light on the dashboard " I incorrectly assumed you meant the latter.

The car in the video appears to be a series 2 model with the regulator in the rear wing near the battery. Tell your Tech the regulator for a 1975 SS is located at the rear of the engine bay just behind the windscreen wiper motor, otherwise he will get confused. Also, the video shows someone fitting a GM alternator which has it's own regulator which will also be confusing if he is fitting a reconditioned original.
 

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Discussion Starter · #11 ·
Hi Marc

Could you confirm whether the alternator is a reconditioned CAV original or a substitute modern alternator. When you said your tech was trying to get "the new alternator communicate with the red warning light on the dashboard " I incorrectly assumed you meant the latter.

The car in the video appears to be a series 2 model with the regulator in the rear wing near the battery. Tell your Tech the regulator for a 1975 SS is located at the rear of the engine bay just behind the windscreen wiper motor, otherwise he will get confused. Also, the video shows someone fitting a GM alternator which has it's own regulator which will also be confusing if he is fitting a reconditioned original.
it is a delco substitute modern alternator.......the basic issue is that my tech has no RR experience.....also.....he let the car set for 3 months before he even put the replacement alternator in......
 

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it is a delco substitute modern alternator.......the basic issue is that my tech has no RR experience.....also.....he let the car set for 3 months before he even put the replacement alternator in......
Then he needs to bypass the regulator as I did because the Delco regulator is built in.
 
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