Alternator charging issues

[SamC]

Hi all, after a bit of help if that’s possible please.

 

At the end of last year I had an electrical cut out on my car (CSR260) shutting down all electrics. A power cycle brought it back alive again but from that moment on the battery/ignition light on my dash stopped illuminating when the ignition was turned on.

 

A few miles later and car wouldn’t re start due to the battery being flat and I realised the alternator wasn’t charging.

 

I spoke to a few people and it was presumed that an alternator short had caused the shutdown and I’d just run off the battery since then.

 

I’ve just fitted a replacement WOSP alternator and still have no battery/ignition light and still no charge from the alternator (measured both at the battery and the alternator).

 

There is continuity between the alternator and battery -ve and engine, and there is about a 0.1V drop between measuring directly at the battery +ve and the alternator +ve.

 

Any help on what I should be checking out will be greatly appreciated.

[Jonathan Kay]

Is this a new alternator?

Was the wiring the same as the old one? How many wires and what thickness and colour?

Check the engine earths. 

Have you changed the warning light on the dash to an LED?

And do you have the factory wiring diagram for the CSR? If you'd like one please send me a Private Message with your email address.

Jonathan

[SamC]

Hi Jonathan,

Yes, new alternator.

Identical wiring to the old one. One mount for the positive then a T shaped connector for the ignition light circuit. Same as the standard Duratec alternator - just plugged straight into the car loom).

Engine earths all good. Straps in decent condition and all have continuity to the battery, as does anything metallic attached to the block..

The dash warning light is part of the Speedo unit. Is there any way to check that is functioning?

I have the wiring diagrams thanks.

Edited March 3 by SamC

[Jonathan Kay]

On 03/03/2024 at 17:40, SamC said:

the dash warning light is part of the Speedo unit. Is there any way to check that is functioning?

For standard ignition warning light circuits: 
* Disconnect the plug from the alternator
* Identify the warning light circuit and connect it to earth
* Turn the ignition ON. The light should come on.

https://www.howacarworks.com/ignition-system/troubleshooting-the-ignition-warning-light

Jonathan

Edited March 4 by Jonathan Kay

[SamC]

Yep, earthing that brings the battery light on.

There is 11V on the other pin… seems a bit low?

[Jonathan Kay]

Two different alternators not charging. And a warning light that works when tested but not when connected to the alternator.

First thought is that there isn't an adequate earth from the alternator to the battery.

You could add a good earth with a jump lead and see if the light comes on.

But I think that it would be wise to identify and check every wire and connection in the relevant circuits.

Jonathan

Edited March 3 by Jonathan Kay

[SamC]

Yeah, odd isn’t it.

Jump lead connected directly to the battery and alternator and no light still.

Head scratcher as there aren’t many connections in that circuit are there.

Is the 11V to be expected? Battery is 12.5V at the mo.

Also, could this lamp circuit not working cause the alternator not to charge?

Edited March 3 by SamC

[SamC]

Just to close this off, despite all looking ok from the outside it turns out it was the T shaped connector that connects the switched ignition feed and warning light to the alternator that was faulty.

I cut the connector off and fitted a new one with fresh crimps and everything works like a charm.

Thanks for your assistance Jonathan. 👍🏻

[Jonathan Kay]

Well done. Thanks for adding the solution.

Jonathan