Mystery wires... driver's footwell

Troubleshooting
1

Hi
I have a '92 GTO TT ex Japan.

I am trying to diagnose why my instrument lights/dimmer has recently given up the ghost. I’m getting up to 7v from the rheostat but nothing lights up… I’m now going through the connectors trying to trace how far that 7v gets! The importer bodged the rheostat/switch wiring to feed a fog lamp, I’ve now fixed that.
(they’d fed the fog lamp switch from the green/white (lights feed) wire AND the black/yellow (dimmed feed to instruments) wire).

However, while tracing through the wiring I have found this (see pic) which appears to be a supplementary/accessory harness of some sort. I have searched through the wiring diagrams and forums without success. It appears to be a proper OEM harness which is connected to the main harness.

If it’s a DIY addition then it’s very well made!

It’s a T design with two connectors (the blue and black connector with the blue, white, yellow and red wires is one, the other is hidden) and the three pin and bullet connector.

The three pin connector (R G B) and the bullet connector (W) do not appear to have anywhere to go, hence my thoughts that it may be for an accessory or something.

Anyone seen one of these on their car please?

Paul

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2

Maybe a turbo timer was once in there.

1 Like
3

Thanks, I’m wondering if I can safely remove it… I might give it a try.

4

If its just a t, then it should be as simple as unplugging it and plugging the factory plugs back together.

1 Like
5

I’ll give it a go tomorrow :+1:t2:

6

I’ve removed it. Nothing broke :slight_smile:

Thanks

7

Not sure how helpful I’m going to be here but I’ll share my experience nonetheless.
I also had an excruciating time diagnosing cluster/interior lights. Sent the cluster off to be refurbished, didn’t help, changed with LEDs, didn’t help, drove myself crazy with a multimeter, didn’t help. Turned out to the be dimmer switch which seems to have a mind of its own, even just from the vibration of the engine running. Ripped that sumbitch out, pinned the connectors and have been problem-free ever since. I never dim the lights anyway. Might be worth a luck if you’re still having issues.

8

Hi, yea, I’m having fun too… and yes the dimmer is the problem with mine too. I’ve done the test suggested in the repair manual and it’s duff.
I have sourced a replacement that’ll arrive soon… hopefully sorted.
Good suggestion to take the switch out too. The dimmer seems to be on the ground/earth side of the circuit which seems odd to me, but I am more used to ancient british cars… :thinking:
Cheers