Alternator not charging.

[guv.c]

Hi all. I'm sorry if this is a bit of a long read, but I always tend to do this! Hopefully it may help someone in the future1

Just got myself a small polo 1.4 16v petrol 2003 model, 9n. Engine code bby

Had done 400 miles in it with no issues.

Then on monday, decided to go to bham in it. On the way there is was fine. In fact I was pleasantly surprised, was doing good speeds, and was very very stable for a small car. But on the way back, the problems started.

First of all, the battery light came on. Didnt seem too serious, I slowed down to 60, and I thought I'd call my uncle ( very old mechanic), and ask him what to do. Then before I got my handfree on, the battery light flickered off. I though, problem was gone, so I sped up a bit. All dials were looking good.

Then all of a sudden, loss of power steering, loss of abs brakes, loss of power assisted brakes, most of the warning lamps were on, but all of the gauges were stuck! It was not a good situation. Then I realised there was no power anywhere. Couldnt indicate, couldn't open widows to stick my hand out to indicate! Didnt want to stop on the m40, so got to J6, took it off and ended up at the lambert arms! Lovely place. however had a totally flat battery.

Called a tow truck. He put his beefy power pack on the battery, started it, and kept it connected. Everything seemed ok, so drove it onto the truck with the pack still on.

Then the truck started to overheat!! but i digress

Got home, got the car off the truck, bumpd it on the way down, started fine, but engine mngment light was on. turned it off, disconnected battery and put it on charge. Took the alternator out, checked the brushes, which seemed fine.

Today, after lunch, I took the batter off charge and tested it the best i could. It seemed healthy and was holding a good charge at about 13 volts.

Then I started reading up and I saw some posts about this blue cable from the alternator, and the dash battery light. So I put the connections back on the alternator, connected the battery, and turned electrics on, and the battery light did not come on. So disconnected everything, and started tracing the wire.

Under the car, the wires at the connecters seemed fine o(both wires, both connectors). I pushed a pin into the wire after the second connector and the wires were fine, not broken (which as I understand is a common fault).

Took the instrument cluster out, and on the 32 pin connector tried to buzz out blue wire on number 15 to the blue wire that plugs into the alternator and there was nothing, it was open.

But when I put the ignition on the blue wire has 12v and the red one had 5v (using chassis as earth)

Ok so after connected everything back together, put meter on the battery, it was reading 12.5v. put the ignition on, 12.3v. Started the car 12.1v. Turned on all electronics. 11.8v. So I think the alternator is not doing its job.

Right now, with a charged batter, the car starts, and drives fine, but the epc light and the check engine lights are on with ignition. When the car starts, the epc light turns off but the check engine light is still on. Now I'm a little stuck.

Should I rip out the alternator and send it to a specialist? or go back to the blue wire, (and the red one)? Are we sure that the blue wire goes to pin15? Where does the red one go? Are the supposed to get voltage with ignition on? If the alternator is dead, then why do I not have faulty alternator light on the dash? Should I take apart the dash?

Any help would be much appreciated. so many many thanks in advance. and very sorry for the lengthy read.

Guv

[Crasher]

If the alternator light came on, the blue wire is OK, you need a new alternator. Don’t prat about getting the alternator overhauled, go to someone like GSF and get an exchange unit.

[slicker55]

Hopefully it may help someone in the future

Thanks Guv for relaying your story - interesting read and yes, useful to anyone trying to trace a similar fault - how did things turn out in the end - did you eventually find the fault?