any one really good with electrics

[Guest cortinamad-gonetoo]

my battery light is on dim and alternater and battery checked and fine

 

once i had this problem in a pinto sierra and a electrician fitted a diode and that was the problem solved

 

but which wire would he have fitted it to and what sort of diode.

 

will it be the wire going to the batery light?????????

[evil knievel]

i'm going to sound like a right cock now but, is the belt slipping? and are all connections clean?

[mk3cokebottle]

even though the alternater is showing they are fine it still could be on its way out , is the light on when you have you lights , heater , stereo on ?? if it is it could be that when you have them on the alternater is not powering up enough but still charging so not really a problem its just showing that the charge isnt as powerfull if you rev the car the light should dissapear

[evil knievel]

just read your other thread

 

are the lights dimming badly etc? even with the different alternator? as it could be a problem with the light itself and just coincidince.

 

But it sounds a little bit like a short some where, because of the drop in voltage when the lights are on. Try testing it with lights off but loads of other stuff on?

[Guest cortinamad-gonetoo]

yeah exactlly same problem with 2 different alternaters so unlikely to be alternater

 

the light is on dim but gets slightly brighter when i brake or indicate or put wipers on

 

i can only see it on a night as its not coming on bright enough to see during day

 

when i rev engine it gets brighter

[Guest cortinamad-gonetoo]

oh and yeah fan belt is ok and connections

[evil knievel]

It's all happening the wrong way round

 

Lights getting brighter when you brake, battery light coming when you rev it

 

I'm extremely confused!

[aden]

it sounds to me like the rectifier in the alternators on its way out mate, it bascally consists of diodes which convert the AC from the alternator into DC, its probably this you had replaced before mate

when its under load the battery light comes on brighter because it is struggling to provide enough power, if every thing else seems to be ok i would look at that

[aden]

just see you have the same prob with 2 alternators

[evil knievel]

Yeah I was thinking rectifier until I noticed the 2 alternators

[livewire7116]

there is always chance you have 2 duff alternators of course?

[Savvi]

As i said in the other post, could well be an earth or a bad connection on the ignition side (the light has an ignition feed )

 

I didn't think the output was all that good myself from the figures you stated, with either alternators.

 

 

If your near Oxford call in

[w p e]

bad earth from engine to chassis or a couple of dry cells in the battery[ lack of water]

[Guest cortinamad-gonetoo]

no none of those as i put jump lead straight from battery earth to alternater body and ive tried yet another alternater and battery from another mk5 cortina and still same

 

i also fitted a test light in place of battery light so its not wiring up to the battery light as it still does it

 

i took live straight to alternater main wire and still does it

 

wtf is it aaaaaaaaaarrrrrrrrrrrrrrrrrrrrrrrrrrrr

[Andrade]

no none of those as i put jump lead straight from battery earth to alternater body and ive tried yet another alternater and battery from another mk5 cortina and still same

 

i also fitted a test light in place of battery light so its not wiring up to the battery light as it still does it

 

i took live straight to alternater main wire and still does it

 

wtf is it aaaaaaaaaarrrrrrrrrrrrrrrrrrrrrrrrrrrr

 

Is it causing any other side effects apart from the bulb coming on? Like the front lights brightening and dimming when you rev the engine? or driving for an hour at night then having to pushstart the car in the morning?

[Guest cortinamad-gonetoo]

it starts ok not flattening battery yes lights go slightly dim at low revs but they always have done ever since i got the car with any alternaer or battery

 

i must stress its not the alternater or battery

[Andrade]

it starts ok not flattening battery yes lights go slightly dim at low revs but they always have done ever since i got the car with any alternaer or battery

 

i must stress its not the alternater or battery

 

well... if it is not causing any new trouble, it is not the alternator, nor is it the battery, nor is it the wiring loom, nor is it an earth... and it does not turn on bright as much as when you have the ignition on, you dont have any problems

 

The same thing you described before happens on my viva too:

 

the light is on dim but gets slightly brighter when i brake or indicate or put wipers on

 

When I brake it gets a bit brighter, I have a brand new battery, and a perfectly fine Ka alternator off a low mileage engine (engine is a 1.3 pinto)