Battery Light Is On On The Dash

[Anton green 12 1 Cars]

My 205 battery light is on on the dash with the engine running and I have already swapped the multiplug, oh and the alternator has only done about 1000 miles too...

 

At engine idle speed the light is fairly dim, and it gets much brighter at higher revs

 

Im thinking I want to be checking for 12v coming through the spade connector on the alternator, then check it is actually making a good connection with the alt. Is there anything else I should check out while I'm doing it?

 

Cheers, Ton

Edited May 10, 2007 by Anton green

[johny105_y2k 1]

check your charge rate.

if thats ok your field wire could be corroded.and be grounding causing it to become a circuit therefore your bulb lights up.

or could be dikky elecs which is very common

[Anton green 12 1 Cars]

This is annoying, I cant use my car as it will only start once, then drains itself of electricity so wont start again.

Just like to say, I dont know what the purpose of the alternator field wire is, but...Today I took the alternator field wire off and the batt light on the dashboard disappeared, does this mean there is most probably a short somewhere on the field wire? Can I get around the problem of tracing the short on the field wire by running a new wire to the alt, and if so where is the other end of this wire to be found-at the multiplug maybe?

 

Cheers T

Edited May 11, 2007 by Anton green

[Mikey G 3]

The small single wire you refer to is the trigger to kick the alternator in aswell as provide a warning light if the alternator fails.

It supplies 12 volts to the voltage regulator through the dash bulb, when the alternator is idle it earths the dash bulb to ground causing the light to come on, when the alternator spins up and the voltage is equal from the dash light to alternator the light goes out.

 

I would say you still have a dodgy alternator, i have seen people buy recon units and still dont work!

[Anton green 12 1 Cars]

Every now and then when I corner sharply the dash light goes out which also makes me think theres a short somewhere..

 

Would you know if the alt wire passes thruough the multiplug?

[Mikey G 3]

Depends which multiplug you are on about and wether its an 8 valve engine or the Mi16 in your signature.

 

The Mi loom runs through the multiplugs that go into the near side corner of the engine bay that you then extend into the dash plugs. The alternator wire is normally brown.

 

The 8v loom doesnt run the extension but it may go to the brown multiplug in the sensor loom attached to it near the gearbox. Its been a while since ive seen 8 valve wiring though so i'm not 100% if the alternator is in this plug.

[Anton green 12 1 Cars]

Yes my 205 is 16V as in my sig.

 

If I were to replace my alternator field wire, where would I start with this project?

[Mikey G 3]

Not sure if replacing that wire is what you need to do, but it would involve tracing it back from the multiplugs under the drivers side dash.

 

I have a funny feeling you may have your wires crossed... so to speak.

You mention the light goes out when you go around a bend, maybe the oil pressure sender is connected to the alternator? and a bit of oil surge is flickering the light off and on?

 

Maybe another option is to test the alternator another way, setup a new wire to the alternator from a known 12v supply, through a bulb (maybe an interior type light bulb) tosee if this cures the problem. You will then know if there is a problem with the wiring.

[Anton green 12 1 Cars]

I'll give that bulb thing a go.

 

My wires havent been touched -This problem just appeared one day