Xantia Phase Two - Mysterious Light

[Futuramic]

Fresh from the girly men topic I'm here to confess that I'm baffled by something.

The car is a fetchingly spruce green Xantia berline. 1.9 Turbo D for powahh and economy. To the lower right of the dashboard are a series of switches: rear window over-ride etc.

Upon this panel is a switch blank with a big red light stuck in it. Said light appears to be aftermarket. Initially I assumed it to be related to the alarm or something. Apparently not! It doesn't appear to do anything at all, except...

When swapping rapidly from right to left hand indication, or vice versa, it flashes! Once or twice and not in time with the indicators. It doesn't do it every time - but this is definitely the trigger. I can persuade it to illuminate by flicking the indicator stalk about.

Can anyone offer any suggestions?

[marmitemania]

Tow bar socket warning light. Does it have or has it had a tow bar?

[anonymous-user]

Does it have a towbar and electrics? These are often fitted and I believe flash when the trailer indicators are working. Or something like that.

[Futuramic]

Thanks! It does have a towbar fitted with two electrical sockets (looks like a proper Citroen item). That's probably it. I've never used the towbar by the way.