Battery Light always on

[SKoob]

I've put a different engine and a mk2 dash into my car and now the battery light is always on, i've changed the altenator to the original one that I know works, yet it is still on :wtf: can someone confirm which lead goes on which connector and if there's anything else causing it :thumb:

[Adam]

Thick red from alt to starter/batt
Thin blue/white to alt from dashboard battery light.
Earth between the alternator and engine/inlet

[AlexW]

Had this prob on mine, i even checked it and it was producing 14volts so its fine.

[chris gsi]

check the earth pionts on the car as it may just be a bad earth at fault

[SKoob]

I'm still having this trouble and a known good altenater is not charging the battery, its really starting to annoy me as i have the car on the raod and can't use it :( I've checked, checked and checked again and still can't find the fault. I've even been consulting the haynes manual wiring diagrams but can't seem to workout how the circuit is made from the charging light to earth :confused: anyone good at reading these able to give me a pointer? cheers lol

[AlexW]

So its not just the light? Alternator not charging the batt or have i missed somthing?

[SKoob]

alternator is not charging the battery, i've been told that it relys on the circuit with the warning light in to charge the battery :confused:

[AlexW]

AFAIK it dosnt? So if you put a mutimeter across the batter what voltage do you get? While running.

[staggy_gsi]

is the earth wire from the alternator to the engine present/good condition? had a few of these corrode before now

[Adam]

alternator is not charging the battery, i've been told that it relys on the circuit with the warning light in to charge the battery :confused:
It does, the light bulb wire gives the alt the initial current to start it charging. Once its charging the alternator sends current/voltage back up the light wire meaning theres equal voltage on either side of the bulb, so it goes out(no earth connection)

Id go with staggys suggestion, check the engine earth and alt earth

[saloonwoody]

mine did this it was the battery light diode burned out but mine did charge ? trapped a wire anywhere ? or yea the earth , try puttin a jumplead from alternater to engine somewhere see if that works

[SKoob]

I was thinking it could be the earth lead, but its got new earth leads from the alt to inlet manifold stud and from engine to gearbox, other thing is the brake fluid warning light stays on too :confused: I've recut and joined all the wires again to try and eliminate the possibility of dodgey connectors. Saloonwoody, is the diode dials related or altenator? Really contemplating a complete mk2 loom lol