TU9 charging system, help needed

hammerong · Unread post by **hammerong** » 06 Apr 2010, 15:36

I have a citroen ax10, I took the aux belt off today as the car wasn't charging. I found this (see pic).

I also noticed next to the alternator there was a thin wire with a spade connector on the end, not connected and there is a post on the alternator marked 'B' with no wire going to it and no wire anywhere that looks like it would attach.

Can anyone help fix my charging system, preferably with pics.

Thanks
Olly

spider · Unread post by **spider** » 06 Apr 2010, 15:52

That belt is dead

Check the pulley's for any old debris from it before fitting the new one.

There's a chance the alternator will be damaged if its been run with the exiciter wire (the little thin wire) disconnected.

99% of modern alternators have internal / onboard regulators so wiring is simple (one heavy lead to the battery / starter or somewhere sensible) and the thin exciter wire that is ultimately connected to the charge warning light on the instrument panel.

You can 'test' the thin wire (well, the charge bulb) by connecting the thin wire to earth (warning: do NOT have it connected to the alternator at the same time!) the charge light should come on with the ignition, if not check the bulb. Insulate the thin wire from everything and check the charge light goes off.

The thin wire goes to the D+ connector (the little one on the alternator) , the large one is normally marked B+ but its size is obvious.

If in doubt: STOP and ask before doing anything, don't want you to cause any damage.

hammerong · Unread post by **hammerong** » 06 Apr 2010, 16:14

It has a thin green wire going to the alternator, already plugged on. The disconnected wire is brown with what looks like a red stripe. It also has a thick wire with a black rubber cap.

This pic MAY help, but probably not. I wish I had my multimeter, it'd make fixing this easy.

spider · Unread post by **spider** » 06 Apr 2010, 17:07

I cannot make that picture out properly. I tried editing it to lighten it a bit but it did not help, don't worry I know its a right pain to get good pics in difficult spaces.

The large terminal on the left of the pic is intended to be as-is as far as I know.

If you have the thick heavy lead and the thin 'exciter' wire connected you're good to go as it were...

The 'spare' thin wire may intended to be not connected. Is anything else nearby unplugged ? (oil pressure switch springs to mind actually)

hammerong · Unread post by **hammerong** » 06 Apr 2010, 18:24

Thanks, the moment you said oil pressure switch it clicked, the car has an aftermarket oil pressure gauge fitted with a big cylinder bolted to the front of the engine with a wire coming out of it.

The ECU doesn't need the signal does it? Or is it purely there for the oil light?

Thanks for your help, I'll replace the belt and check to see if it's charging.

spider · Unread post by **spider** » 06 Apr 2010, 20:03

hammerong wrote: The ECU doesn't need the signal does it? Or is it purely there for the oil light?

I am not 100% sure to be honest, I doubt it would use that, although it would make some sense (regarding operating the fuel pump) but I doubt it does use it for anything.