What does this cable do? '82 SC

[felix83]

I'm currently removing an old aftermarket alarm, and in the process I stumbled upon this rather interesting-looking installation on the floor under the passenger side carpet (Euro-spec car). The grey wire looks to be factory fitted, the red and black ones, not so much. The grey one continues alongside the tunnel, possibly via the heater control console, and into the engine compartment. The red and black wires continue into the boot where they join another grey wire of the same type as before. This wire stretches back into the cabin, possibly towards the roof.
Could this be the wire from the cabin temperature sensor (by the sun visors)? If so, that might explain why my auto heat acts as though it doesn't get a signal from that sensor...
I've looked at several wiring diagrams of the heater unit, but none stated the colour of said wire.
It's a bit odd why one would want to splice a wire in this fashion, but after looking at the way the alarm was installed, nothing surprises me...

[john walker's workshop]

not stock. follow it to find out.

[javadog]

Looks like the cable for the interior temperature sensor, in my opinion. Unwrap the tape and have a look at it. The stock cable is a light grey (almost white) coaxial type of wire, roughly 2.9mm in diameter. There is a center conductor and a braided ground enclosed in the sheath. It has a molded connector at the end that attaches to the sensor. It runs down the right side A pillar into the trunk (boot) just forward of the dashboard structure on the right side, at the top of the right inner fender. It then is routed through the passenger compartment to a 2-pin connector that mates with the auto heat controller.

Obviously the spliced red and black wire are not supposed to be there.

JR

[felix83]

Originally Posted by javadog

Looks like the cable for the interior temperature sensor, in my opinion. Unwrap the tape and have a look at it. The stock cable is a light grey (almost white) coaxial type of wire, roughly 2.9mm in diameter. There is a center conductor and a braided ground enclosed in the sheath. It has a molded connector at the end that attaches to the sensor. It runs down the right side A pillar into the trunk (boot) just forward of the dashboard structure on the right side, at the top of the right inner fender. It then is routed through the passenger compartment to a 2-pin connector that mates with the auto heat controller.

Obviously the spliced red and black wire are not supposed to be there.

JR

I tracked the wire this evening, and it certainly seems you're right. Thanks for your input!