Really annoying electrical fault!

[beetlebum2_uk]

I'ved had my 340 saloon since about august last year and is by the best car i've owned. cant' fault it 99% of the time.

there is one little problem which doesn't affect anything just niggles. when i'm driving usually motorways or above 50mph the battery light on the dash flickers on and off. and has come on and stay on for a couple of minutes before going off again. this has never affected the car it starts everytime and never cuts out, plus i always have the radio on and this doesn't die either.

can anyone suggest what this could be?

cheers in advance joe.

[jarlidge]

hi

you could check the fan belt, it might be slipping or be a worn pulley.
that could be why it causes the battery light to come on when you reach a higher speed.

cheers
jeff

[classicswede]

99% it will be the brush box on the alternator.

[beetlebum2_uk]

are these interchangable or is it a case of a new alternator?

[classicswede]

I've never done it myself but you should be able to. its normaly two small screws/bolts on a plastic plate at the back

[beetlebum2_uk]

cheers. if it isn't that easy how much is a new alternator?

[mac]

I concur with Dai, almost certainly the regulator/brush box. The Paris Rhone brushes are prone to quite rapid wear and a flickering warning lamp is the first sign. The unit also has overcharge warning (on most versions) and this is also a common problem. Usually though it's just the brushes.

It's an easy job - you don't even need to take the alternator off. The brushes are part of the regulator unit (black plastic box on the rear of the alternator held on by two hex head machine screws (8mm spanner).

The "B14" unit is all black plastic, and the "B17" unit has a finned alloy heatsink on the back. You will probably be able to get a replacement from an auto electrician or factors (last time I bought one was from Lucas for about £12.00 - but that was several years ago) Paris Rhone (Valeo) alternators have been used on the 300/400 series cars and lots of frog motors as well so you should be able to source spares ok. Try to get the correct version (the same as on your car) but in extremis a "B17" (or even one from a 440/480) would physically fit to a "B14" alternator (and vice versa) and would work after a fashion.

When the regulator unit is off check the slip rings for excessive wear and if badly grooved it would mean a strip down for a re-face or an exchange alternator (Euro parts still list for about £80). I "googled" "Paris Rhone / regulator" this afternoon and quite a few came up on "the bay" for about the £10 mark.

The other cause of a flickering warning lamp would be a diode failure (in the rectifier) which would also mean an exchange alternator (unless you're very confident in your diy skills). The Paris Rhone unit is not however prone to diode problems and I would certainly go the "brush" route first.

Mac.

[beetlebum2_uk]

cheers for that most of it went straight over my head but i'm sure i'll figure it out!

[Ronnie]

Hey, the Logos is back!

[classicswede]

Hi Mac,

impressed with the desription of how to do it.

[mac]

I try, I try, or at least the wife says I'm always very trying.

Mac

[bogbasic]

Don't do what I did. I soldered new brushes into an old regulator. A few months later it died on the M3. After that, my bias would always be to fit a proper recon alternator. You can get them on the bay for not much more than a new regulator.

[classicswede]

A complet brush box with regulator is not much more than the postage for a complete unit. In a lot of cases this is all that will have bene done on a refurb unit apart form a good clean.

[beetlebum2_uk]

cheers anyone know where the best place to get a bushbox from is? will gsf stock them?

[bogbasic]

http://cgi.ebay.co.uk/Volvo-340-343-345 ... dZViewItem

Herein rests my case.