Wiring questions for 1972 TC (Fed version)

[460384]

What is the black-green wire for?  What is the small box that the wire connected to? My black-green wire was cut on the other end and would like to fix it if I can. Please advise.

[BDA]

That looks like black with a green tracer. From the Lucas wire color code, it's supposed to be either the windshield wiper switch to wiper (single speed) or the relay to radiator fan motor wire (http://lotus-europa.com/manuals/misc/electrical/lucas.html). However, the radiator fan motor wire is likely only in the front with the radiator/otter switch/fan, not in the cabin and the wiring diagram shows the windshield wiper wires to be light green with a black tracer (http://lotus-europa.com/manuals/misc/electrical/tcsearly.gif). I'm not sure about the older style column switch group but given the wiring diagram, I would suspect that it has something to do with the windshield wiper. Does it work? Or maybe a better question is what doesn't work...

[LotusJoe]

I think that is the switch on the steering column that goes to the buzzer. It goes off when the key is inserted. Probably cut to kill the buzzer  . I suspect it makes a ground connection when the key is inserted.

[460384]

Thank you for your replies.  After looking at the both documents, I think this "black with light green" wire is for the vacuum brake switch to warning light and/or buzzer. My car no longer has the vacuum brake system, may be why it is no longer needed.

[460384]

By the way, my wiper and radiator fan work.  The reason I saw this wire, because I was trying to locate the blue wire from the back of my TPI-Tech speedometer to set up the calibration button on the dash.

[BDA]

Looking at my copy of the wiring diagram in the workshop manual, it doesn't appear to be the key buzzer as that uses a white/green and purple wires. I don't think the brake warning light is in any way related to the vacuum boosters. It is triggered by the pressure differential warning valve. That could have been taken out with your boosters but there doesn't appear to have a green/black wire associated with it.

I was about to say I don't have that wire because, I have a newer TCS but it looks like I do! Unfortunately, I wasn't able to follow it very far without achieving the "Lotus Position". Maybe later, I'll take my steering wheel off and see where it goes. Until then, I would say that if it ain't broke, don't worry about fixing it!