[SOLVED] Indicator blinking at double-time

[benoliver999]

My left indicator goes twice as fast as the right one!

It's been happening since I took it in for a service. I got them to remove a tow ball, I suspect it's related to that.

The right indicator goes at 'normal' speed still.

Could this be the case? I could go back but if it's an easy fix I'd rather not!

[Buki]

This usually happens when one of the turn signal bulbs on this side is burned out.

[Gadgetman]

It can also happen if there's a poor connection in the switch on the stalk base.
(Happens sometimes on my M49)

[cancunia]

The indicator speeds are (were?) governed by the resistance of the bulbs. Only 1 bulb would mean the light would stay on. IIRC, to stop the indicators flashing madly when connected to trailers, a special flasher unit was sometimes used. Why it's only on one side is a mystery though!

[oilyrag]

Might be worth checking (if the now removed tow hitch had electrics) what happened to the wiring loom that had been spliced into (possibly) one of the rear light supplies. I recall fitting a socket that had an additional 'trailer' relay/flasher unit that operated the trailer lights.
Modern flasher units don't rely on the resistance of the bulbs and flash at a constant rate.

[Tomcat3]

I would check the bulb too for poor connection in its socket on the offending side. Ive had this before where the indicator is clicking a lot faster and on looking at all the indicators they are working but on closer inspection one of the bulbs was not making good contact with the holders contacts. A quick clean and all back to normal. This was on an 2008 M59 model

[benoliver999]

Interesting answers, thanks. The bulbs are working but I will check the contacts.

The tow hitch did have electrics, they said they tidied it up but I presume there's a chance they left the extra relay on.

[benoliver999]

It was the extra wiring that'd been left spliced into the rear left lighting holder. Luckily they'd used the same connector, so it was a case of simply un-plugging it.

Meanwhile a headlamp went, and it was a right job trying to get the cover back on...