Weird Light Problem

[Guest mcramsay]

Here's a weird one for you, if my lights are off at the stalk switch as soon as I rev the engine the lights come on dipped beam, I'm using zetec with jenvey and emerald set up with an acewell dash. Any one got any ideas where to start looking? The pedal doesn't touch any wiring as it moves...

[Guest The Modfather]

Have you tried it with the dash disconnected? It is strange as the lighting circuit should be seperate to the charging circuit. It sounds as though you are either getting a pulse from something or a surge that is somehow connected to your light circuit.

When you stop revving do the lights go out? Is this a new problem?

Are you currently building your car and have just encountered this, or have you changed something recently?

[Guest mcramsay]

Still building, I think it's prob been there for ages I've just never noticed. It only happened if I go over 1000 rpm so I think it's to do with the charging circuit! I don't know tho! Look more in depth tomorrow!

[MarkBzero]

I agree with Daz sounds like charging not sure how the jenvey and emerald is set up but on a normal engine set up I would consider disconnecting the alternator electrics and see if it still happens.

Regards

Mark

[Guest mcramsay]

I will give that a go in the morning, but surely the charging circuit would blow the light fuse?

[Guest mcramsay]

ok ive had a bit of a play today and heres what ive done/the results of what ive done

 

i swapped the supply for the headlights from a constant to switched live, when the engine revved over around 1000 the lights came on.

 

when the lights turn on the indication lamp on the acewell digidash does not light up so the lights are coming on and bypassing the dashboard lights.

 

i disconnected the main charging wires that go from the alternator to the battery. with these disconnected the lights did not come on.

 

i let the lights come on and then removed the dipped beam relay and the lights went off.

 

it looks like its charging circuit related. but im now completley stumped!

[Guest mcramsay]

whilst writing the last post i realised what could be the problem. the denso alternator has two connectors at the back. one for the dash light and one switched 12v supply. this 12v supply is linked in with the relays for the switching voltage. so i disconnected this wire and reved the car, and the lights didnt come on! i then replaced it and started the car again and revved and the lights came on. so it looks like this wire is some how interfering with the lights. i will change where the feed for this 12v supply to the alternator comes from and hopefully that will solve the problem!

[Guest The Modfather]

Well done for tracing it.