My electrical woes continue

[Puggy2]

At the weekend my heated seats stopped working yesterday I driving and noticed my wipers where slow later in the day it died on me completely flat battery wife towed me home lucky only half a mile. Took battery off and charged overnight refitted it start engine fine, turned ignition off then back on and I noticed no battery light,started engine again battery voltage falling not charging.Does the alternator have a fuse for primary feed?

[hasler88]

I don't think there is a fuse, does the batter light come on when the ignition is on but engine not running

[Doggy]

Could be the auxiliary connection to the alternator - the small wire - is it securely connected?

[hasler88]

Put a multimeter on the larger terminal of the alternator see if there's anything on that

[jasper5]

Sounds like alternator failure or alternator pulley slipping.

[Ares]

Had similar problem like you.
Battery was slowly dying so i replaced it overnight with new one,still not charging.
I had the battery warning light oon it,replacing the alternator didnt solve anything,so with new alternator and battery,all that remains is wires between them so perhaps you should check that too.

[PeterN]

As suggested could be failure of the exiter supply from the battery light, check the small terminal on the alternator, should be 12v there with the engine runnning.

Peter

[Puggy2]

No voltage on small terminal, is it time to remove instrument panel to check battery bulb

[PeterN]

Afraid so, its unusual for the bulb to go but possible, otherwise could be a fault in the wiring, the edge connectors on the instrument panel can be prone to dry joints on some cars although I have not yet experienced it on a 406.

Peter

[jasper5]

At the weekend my heated seats stopped working yesterday I driving and noticed my wipers where slow later in the day it died on me completely flat battery wife towed me home lucky only half a mile. Took battery off and charged overnight refitted it start engine fine, turned ignition off then back on and I noticed no battery light,started engine again battery voltage falling not charging.Does the alternator have a fuse for primary feed?

Are you just looking at repairing the battery light or repairing non charging of the battery as well?

If the rectifier in the alternator has failed you will get lack of charge and no battery light.

What is the voltage at the battery with the engine running? Do you have 14 volts?

[PeterN]

You can check the alternator by running a 12v feed to the small alternator terminal, it should then charge if OK.

Peter

[Puggy2]

I think I have 2 issues.

1 I grounded the small wire no light on dash, checked my wifes car, wire on or off or the ignition light lights then I remembered the ignition light comes on with first position of ignition switch. So is it the bulb,faulty plug connection on back of panel or a break in the cable the only place I can think of is where it joins the harness to the left of the oil filter.

2 Tried putting live to small terminal from big terminal no charge battery voltage still dropping with engine running. Can an alternator fail for having no field voltage while spinning at engine running speed for a while.

[lozz]

Have you checked the earths?

earth strap all good?

[PeterN]

If you definitely had 12v on the small terminal and it still wasn't charging looks like a faulty alternator. Did you check to see if you do actually have 12v on the large terminal?

Peter

[Doggy]

Tried putting live to small terminal from big terminal no charge battery voltage still dropping with engine running. Can an alternator fail for having no field voltage while spinning at engine running speed for a while.

The alternator definitely won't give an output without an excitation supply, unlike old dynamos, (DC generators), that were self-exciting by virtue of residual magnetism.

I would want to make absolutely certain you have a good solid connecton between the big terminal and the battery +ve, also between the alternator casing and battery -ve.

You can use a jumper lead to prove the negative, then try connecting a light bulb between the big alternator terminal and the casing with the engine and ignition off. It should light.