I'm not really sure which section to post this in so apologies if I'm posting in the right section but I'm after some help/ advice..
We are nearing the end of wiring up our off road car and we have got on to trying to wire the alternator light for the dashboard. We have a supercharged 4.2 jaguar v8 from an s-type R in the back but we are having problems with getting the light to work at all. i.e. it's not even coming on when the ignition is on. I think I have figured out what the 3 wires do in the plug that goes in to the alternator ( brown/ green trace goes to battery 12v, green/ orange trace goes to ignition 12v, and the yellow/ red trace goes to the ignition light) PLEASE CORRECT ME IF I'M WRONG. However, when we put the ignition on there is no light coming on at all. Does anyone have any ideas/ advice?

Thanks in advance.