306 HDi alternator light flashes when engine off

[tmead]

I'm confused by this - sometimes the battery light flashes when after the engine is turned off. No other significant symptoms, although I can't quite decide whether there is a slight change in brightness of the headlights at around 2K rpm - nothing dramatic.
Also, the other day i left the phone charger plugged in and the lamp on that flashed with the battery light. No relay based clicking noise inside the car, so must be solid state2 or under the bonnet.

My suspicion is that its the alternator, but I'm all open to ideas, as that is a hateful job. I can't believe they designed the car so you have to take the oil filter off to remove the alternator... I replaced it for my first time when I had some bizarre symptoms with all sorts of lights flashing on the dash, assuming it was a dead regulator. The secondhand replacement was a lesson to me not to be such a cheapskate - it lasted 4 months. The new replacement is now about 2 years old, so shouldn't have failed yet, but is certainly out of warranty !

Tim

[Peter.N.]

Hi Tim

Under 'normal' circumstances I would say alternator but these modern cars have so much fancy electronics that I wouldnt guarantee it, can you remove the thin wire from the alternator, if you can and it stops, that will be what it is.

Peter

[spider]

306 is not multiplexed so should not be *too* bad.

A no too common fault that can cause this (yes really, seen it a few times) is water entering the rear wiper relay, its under the hatch trim. Whip the trim off an examine the relay for water / corrosion. Unplug it and shake it if in doubt. The main loom plug to that is usually under the OSR C pillar area.

It could well just be the alternator though but I'd have a look at that rear relay first simply as its easy to get at. Less common is the actual indicator switch breaking internally too which can cause something similar.

[tmead]

Thanks - I guess that makes some sense, I was wondering where the regular timing of the pulses came from. The rear wiper was attended to a couple of years ago for water/corrosion, and modified to run with an extra relay so there is no way it can short out and blow the fuse that also excites the alternator (!) again. I'll pop the connector off the motor at the back and see if that makes it go away !
There's no big issue, as the battery isn't going flat or anything. I'm just curious.

Tim