Electrical problems

[Matt]

My car broke down on the motorway today driving back from Bristol

it started by beeping at me and displaying a 'battery charging fault' and the battery light came on intermittently, usually when i was stationary, then after a little while of that all the dials went mental and all the warning lights flashed and beeped randomly then the speedo stopped working and would just stutter finally stopping on 50mph,

then all the power failed and i had to muscle my way over onto the hard shoulder and call for help

is this likely to be a alternator failure or a more serious electrical problem?

I got the car recovered and its at home on my drive right now and i'm charging the battery up to see if it will run, then i'll do some checks with my multimeter but has anyone else had this happen to them before??

Cheers
Matt.

[mjb]

Sounds like the alternator's dead, aye

[Doggy]

I has something similar with my previous Citreon. Went on for a few months, eventually was a combination of intermittent connection from quick-release battery +ve terminal and an internal battery fault. At one point my rev counter went all the way round & stuck against the wrong side of the zero stop! Disconcerting, happened at the Nurburgring

[Matt]

god, i hope i dont have that then, if i dont get around 14v when then the engines running i'm gonna have my alt and battery tested

[Matt]

Right i tested the battery today, its staying at 13v when the engine is off, readings hover around 14v with nothing electrical on, then when i run everything electrical i can including the AC and heated seats its reading around 11v

should it be coming back at around 14v even under heavy load?

Cheers
Matt.

[steve_earwig]

My Ladybird book of Car Maintenance says you should be holding the revs at about 2k.

[Matt]

bugger, i'll have another go in a bit with a helper,

so at 2k revs i'm looking for around 14v ???

[Matt]

tested it with 2k+ revs and was coming back at 11.7v, then i tried it with everything on again and it was 11.7v again, looks like the first time might have been a fluke when the battery had just came off charge

the battery without the engine on was reading 12.7v

the battery charge fault readings came on again as well when i was testing it,

so this is likely to be the alternator isnt it?

[Doggy]

I'd say it's either the alternator, or poor connections between alternator & battery. If possible, measure the alternator output & compare it to the battery voltage, preferably with some load on. If they're the same, (say within 0.5V), then it's the alternator. If you get a significant difference it's a connection problem.

[Matt]

Thanks Dogslife, where is the alternator located on the 406? is it possible to reach the output cables without removing anything or getting caught up in the belt?

[mjb]

Thanks Dogslife, where is the alternator located on the 406?

The same place as every other petrol/diesel powered car

is it possible to reach the output cables without removing anything or getting caught up in the belt?

Depends on the model. You've got no chance on the V6 and the 2.0t could be tricky if memory serves. I don't know about the other engines but it's probably a piece of cake on the 1.6...

[Doggy]

Thanks Dogslife, where is the alternator located on the 406? is it possible to reach the output cables without removing anything or getting caught up in the belt?

It will vary from model to model, but it's dead easy on mine, (2.2 HDi). The alternator's at the front left side, below the power steering pump and above the a/c compressor. The main output & warning light / excitation connections are on the top, rear of the alternator, looking straight at you. Both connections have push on caps, you can remove for testing. There's a clear pic of this in Haynes, (99-2002, page 5A/3, Idon't have the kit to put a pic on here, else I would).

On my car it would be possible to get caught in the aux. drive belt where it goes round the a/c compressor pulley, it's close, but in my opinion, not dangerously so.

If you let us know which year/model/engine you have, someone will probably put you right.

[Matt]

cheers, i've got a 1999 2.0 HDI, with aircon too

[Matt]

i checked the alternator voltage when i got back from work and its reading the same as the battery approx 11.5v

I'll sort myself out with a replacement alternator

Thanks for the help everyone