Not charging but alternator working...

[James D]

Dear all,

I've replied to Jon in mechanical as he had same symptoms only his was a broken wire between alt and starter that was affecting charge.

My symptoms are exactly same i.e. battery not charging BUT there is 14V coming out of back of alternator when running.

However, I've continuity checked the positive coming out of alternator directly with the positive lead connect to battery. There is continuity there even when I wiggle the wire from alt to starter.

As soon as I turn ignition on, there is no continuity only open circuit. This persists when the van is running, hence no charge.

As soon as I turn ignition off, with no red lights on dash, I get continuity back.

To say I'm bamboozled would be understating it!

Any ideas would be greatly appreciated.

Thanks,

James

[ninja.turtle007]

Have you cleaned and checked the terminals on the battery, starter motor and alternator?

[ghost123uk]

I've continuity checked the positive coming out of alternator directly with the positive lead connect to battery. There is continuity there even when I wiggle the wire from alt to starter.

As soon as I turn ignition on, there is no continuity only open circuit. This persists when the van is running, hence no charge.

As soon as I turn ignition off, with no red lights on dash, I get continuity back.

To say I'm bamboozled would be understating it!

You're not kidding James when you say bamboozled ! This is why you have not had any solutions proffered (except for nija's good advice). What you describe is very odd. Continuity from the heavy wire at the back of the alternator, which first goes to the solenoid, then back to the battery, in theory cannot be affected by simply turning the ignition on ! Then the fact that the van starts OK indicates that the main heavy lead from the battery to the solenoid is OK. So, put your probe onto the big terminal on the solenoid whilst the engine is running NOTE = carefully !! not much room around there - Do you still get 14V there ? (well you must really in view of your checks so far )

No, I am stumped. No doubt if I was with you I could suss it in minutes as it cannot be anything too complicated can it. Perhaps ninja is right and a poor connection somewhere on that heavy (red) wire is intermittently breaking down. That or an earth (battery to body or gearbox nose to chassis). Note = sometimes a bad connection can "jump into life" when a BIG load (ie starter motor) is applied, but fail when no big load is present. No, hang on, that doesn't fit your symptoms either really

Ummmm ..................

[Smiffo]

I've continuity checked the positive coming out of alternator directly with the positive lead connect to battery. There is continuity there even when I wiggle the wire from alt to starter.

As soon as I turn ignition on, there is no continuity only open circuit. This persists when the van is running, hence no charge.

As soon as I turn ignition off, with no red lights on dash, I get continuity back.

To say I'm bamboozled would be understating it!

You're not kidding James when you say bamboozled ! This is why you have not had any solutions proffered (except for nija's good advice). What you describe is very odd. Continuity from the heavy wire at the back of the alternator, which first goes to the solenoid, then back to the battery, in theory cannot be affected by simply turning the ignition on ! Then the fact that the van starts OK indicates that the main heavy lead from the battery to the solenoid is OK. So, put your probe onto the big terminal on the solenoid whilst the engine is running NOTE = carefully !! not much room around there - Do you still get 14V there ? (well you must really in view of your checks so far )

No, I am stumped. No doubt if I was with you I could suss it in minutes as it cannot be anything too complicated can it. Perhaps ninja is right and a poor connection somewhere on that heavy (red) wire is intermittently breaking down. That or an earth (battery to body or gearbox nose to chassis). Note = sometimes a bad connection can "jump into life" when a BIG load (ie starter motor) is applied, but fail when no big load is present. No, hang on, that doesn't fit your symptoms either really

Ummmm ..................

It sounds almost as if James is testing through a relay, that is either faulty or wired up wrong.....

Have you had any wiring altered James...??
Is this a new fault on a van that was working Ok last week with no new work done since..??? etc etc

I'm no expert, but your description will need more info eg is it the stater battery...?? do you have a leisure battery etc etc....

I'm sure with all the info, someone will be able to guide you, James

[Jeff J]

Sorry but just to clarify: you are getting 14v out of the alternator when measuring from the alt output & somewhere on the engine(earth) but you are not getting 14v when measuring across the battery with the engine running & the wire from the alternator to the battery goes open circuit between the alt & battery when you turn on the ignition & stays that way with the engine running. The engine also starts & runs ok is that correct? Is it possible a switch been wired into that line to be used as an immobiliser.