Battery Warning Light

[Guest Jonnyround2003]

Should I have an ignition switch live to the bulb as I have a nuntral and battery cable but it won't light up on ignition what cables should I have to it ?

[Longboarder]

Ignition light should have an ignition live to one contact and the other contact wired to alternator terminal D or L or WL or 61 or I depending on what alternator you have. No neutrals or battery connections involved.

 

Nigel

[Guest Jonnyround2003]

Sorry Nigel so how many cables should go to the battery bulb on the dash and what colour ? It's ford sierra wiring

[richyb66]

Depends on the year. But it's pins 8 B (Blue) and Pin 7 Bk/Y (Black / Yellow)

 

Up to 1987 you want diagram 1 (Starting, charging and ignition) Zone L3 and the instrument pack is number 82

 

1987 to 1989 you want diagram 1 Starting, charging and ignition Zone K3 and the instrument pack is number 108

 

1990 onwards you want diagram 1 Starting, charging and ignition Zone K3 and the instrument pack is number 116

 

For up to 87 only, Pin 8 will be 2 Blue wires, other years will be a single blue wire. Pin 7 will be a single wire

 

 

[Longboarder]

Sorry. I was assuming a sierra alternator, lucas/bosch and was half asleep. (Some of the common Denso Japanese alternators need three or even four wires).

Two wires only on an ignition light bulb. No earth. In the standardish Sierra loom, alternator ignition lamp wire is blue, ignition live to instruments and warning lights was black/yellow.

 

Nigel

 

It works on the basis that when engine is not running but ignition is on ignition live current runs through the bulb and earths through the field coils of the alternator causing a magnetic field and lighting the bulb. When the engine is started the rotor has a field to turn in and can generate current, some of which is passed back to the ignition bulb. If the ignition bulb now has 12 volts fed to it from both contacts there is no flow through it and it extinguishes.

[Guest Jonnyround2003]

The bulb did light before on ignition I haven't changed the cables and now it wont ? I have checked the bulb and it works any ideas it has the blue cable one side and black the other side I don't get the diagrams in the Haynes book.

[Longboarder]

Is the ignition light in a sierra cluster or have you put in a separate ignition light you are trying to wire up.

Isolate the blue and black cables you have going to the bulb. The blue should have its other end at the alternator. The black, properly black/yellow should be live when the ignition is on. I will draw up the circuit and post in a moment.

 

Nigel

 

Edited to remove the incorrect pic which showed ignition live starting out from the ignition switch as a black and then changing to black/yellow. Its black/yellow all the way.

Edited September 29, 2014 by Longboarder

[richyb66]

..... I don't get the diagrams in the Haynes book.

 

we'd already guessed that! Good on you for having a bash at it anyway.

[Guest Jonnyround2003]

great thanks guys I love pictures much better !

[Guest Jonnyround2003]

so its black and yellow and black on one side ?

[richyb66]

No, Black / yellow one side and Blue the other.

[Longboarder]

Sorry. Brain pop on my part. I thought for a moment the ignition live started out from the ignition switch as a black and then changed to a black/yellow after a junction. It doesn't! It's black and yellow all the way.

 

Nigel

 

I will alter the diagram back to correct it.

[Guest Jonnyround2003]

cheers !!!

[Guest Jonnyround2003]

Write my cables ones yellow and brown to the alternator right hand side connector the other side of the bulb is connected to ignition switch live which is connected to the oil light which works ?

[Guest Jonnyround2003]

I have no black and yellow has someone used different wiring color