Charging Problem

[cheesegrater 43 1 Cars]

Hi all,

I'll try and tell you as much as I can.

Basically my 1.6 has decided it no longer wants to charge the battery. It pretty much just runs off of the battery seemingly 12v only when you give it a sudden burst of revs will it start to charge at 14v then seem to drop gradually down.

When running the voltage across the alternator is 12v decreasing with what I believe to be the battery voltage. There is continuity between alternator/starter/battery terminals on both +/- and the - and chassis/engine. The flying lead that connects to charge connector seems to do nothing. The charge light remains off constantly (engine running or ignition on) however it came on once whilst running with the flying lead connected.

I've changed the alternator for one I bought off eBay I've also changed the battery and no difference

Any help would be appreciated.

 

Tom.

[Tom Fenton 1,542]

Cut the terminal off the small signal wire to the alternator and crimp on a new one, also check the continuity of the wire back to the plugs at the back of the dash clocks.

[cheesegrater 43 1 Cars]

Cut the terminal off the small signal wire to the alternator and crimp on a new one, also check the continuity of the wire back to the plugs at the back of the dash clocks.

Hokay I'll give that a go, how do I get to the clocks, do I have to remove the dash? If so is it easyish?

[Tom Fenton 1,542]

Haynes manual describes it, not that difficult.

[ade 4wd 11]

The charge warning lamp on the dash has to be connected and working for the alternator to function correctly.

[Anthony 1,003]

Usually even with the exciter wire unplugged or the bulb missing/faulty, the alternator will still "self-excite" and begin charging once the engine has been revved and normally keeps charging for the rest of the journey without issue so long as you don't leave it idling for an extended period of time.

 

Certainly I did over 10k miles in my old Passat like that (and the previous owner atleast the same again) without issue, and recently the wire broke off from the connector on my 205 and I didn't have any issues with that either for a few weeks until I bothered to fix it. 205 needed to be revved to about 2000rpm to start charging, and the Passat nearer 4000rpm.

[cheesegrater 43 1 Cars]

Usually even with the exciter wire unplugged or the bulb missing/faulty, the alternator will still "self-excite" and begin charging once the engine has been revved and normally keeps charging for the rest of the journey without issue so long as you don't leave it idling for an extended period of time.

 

Certainly I did over 10k miles in my old Passat like that (and the previous owner atleast the same again) without issue, and recently the wire broke off from the connector on my 205 and I didn't have any issues with that either for a few weeks until I bothered to fix it. 205 needed to be revved to about 2000rpm to start charging, and the Passat nearer 4000rpm.

That seems to be the case then I've had the clocks out and the exciter wire does not have continuity between any pins on any of the plugs. Are there any other connections other than the ones in the back of the clocks? Does anyone know what pin on which plug should be the exciter wire?

[Anthony 1,003]

It's a brown wire (wire 7A) on the larger 9 pin underdash multiplug, and on the larger blue plug on the back of the clocks.

 

Check that the wire hasn't broken off or has a really poor connection on the brown multiplug in the engine bay, assuming it's still present, as the wires here are typically brittle and the contacts in the connector corroded.

[cheesegrater 43 1 Cars]

It's a brown wire (wire 7A) on the larger 9 pin underdash multiplug, and on the larger blue plug on the back of the clocks.

 

Check that the wire hasn't broken off or has a really poor connection on the brown multiplug in the engine bay, assuming it's still present, as the wires here are typically brittle and the contacts in the connector corroded.

Ok brilliant cheers for that. I've only heard horror stories about the brown multiplug

[JRL 14 1 Cars]

"self-excite"

 

Brilliant one Anthony made me laugh because it sounds sort of naughty.

[cheesegrater 43 1 Cars]

Broken wire between brown multiplug and alternator

Cheers guys.