Triumph Repair: cigarette lighter replacement/wiring, spitfire 1500, purple wire

Question
Hello,

I just bought a replacement cigarette lighter for my 78 Spitfire 1500 and can't figure out exactly how to hook it up.  The original only had a wire from the bulb on the side of the lighter unit hooked up to a red and white wire.  The new unit came with a small black wire with connectors on both ends and a red wire coming out of the bulb.  The connection on the end of that wire did not fit into the connector for the original one so I spliced the wire.  There is also another red wire that came with it which has a covered cylinder connector on one end and a regular cylinder connector on the other.  There are a couple of stray black wires behind the dash that might connect however it wasn't hooked up when I got it, although it had been used. It is killing me!! Any advice?

Answer
Hi Ethan,
I can tell you what wire does what on the old unit but you will have to either look at the new unit to figure out what wire does what or if it came with some instructions.
The center post on the back of the old lighter was a straight plug in purple wire. Purple wires are hot all the time and usually unfused. The red with a white tracer is a light bulb that is hot when head lights or parking lights are on. Usually the outer metal retainer of the lighter that secures it in, has a flat spade connector on it for the ground (black wire)
locate these wires in the area and test them with a test light or volt meter to confirm what they are.
Look on your new unit for a center connection which should be the lighter itself and should get the purple wire from the car. Locate the center light bulb connection on the new unit and connect it to the red/white wire from the car. If there are any other connections on the new unit, they are most likely grounds which would go to black wires on the car.
The colors I am telling you about on the car are original wires. If you can see someone has done some wiring in there, they may not have followed the correct color coding.
If you will use a test light or volt meter you will be safe.
Good luck, let me know how you do.
Howard