Just been out in the car, the left indicator is flasing rapidly….is this a faulty bulb or something ?

The other bulb may have blown or a dodgy earth

Probably a bulb gone. Easily checked…

Usually 1 of the bulbs has blown

or…an old style bulb replaced with LED?

You made it all the way from the car to the internet to ask that, rather than walking round the car?

You made it all the way from the car to the internet to ask that, rather than walking round the car?

I walked around the car first to see if any bulbs had gone, but no.

Hence the question on here !!!

Flasher units work on resistance, so if it's going fast it is seeing a high resistance when switched on to that left side. As no bulbs have gone, then as mentioned above – have you fitted LED replacement bulbs? If so, then you will need a ballast resistor wired in parallel to the bulbs to simulate the expected load. If you have normal bulbs, and they are flashing OK, but faster on the left, then you undoubtedly have an earth issue. One of your left-hand indicator bulbs is not earthed directly. Most commonly happens with tail lights. Check all the wiring from the left-hand rear cluster, and make sure it has a good earth.

What type / age of car is it?
Do you have a towbar fitted (and wired)?

If all the bulbs are working it could be a bad earth making the car think a bulb has gone, get someone else to sit with their foot on the brake pedal whilst the indicator is on and see if the rear light clusters perform strangely (i.e. all lights flashing, or the 'pulse' of the indicator making other lights flash too). If that's happening remove the cluster, clean contacts are try again.

alternatively most cars/makes/models have forums too, you could join one and ask.

great minds etc etc dave_aber 😉

Tow bar fitted last week.

Tow bar…that'll probably be it. Take it back if you don't want to get your hands dirty.

How much do you want to bet its a dodgy scotch lock connection from the towbar fitting, bloody useless things.

Dodgy scotchlocks shouldn't be able to increase the resistance in a given leg, unless they have cut right through the cable of course. Should be banned anyway, just for being shit. Still, recent change being the towbar fitting has got to be a good pointer.

TBH modern flasher ('90+) units usually rely on a little microcontroller, not resistance, the old style did. If it's not any of the bulbs and theres no earth faults, you may be looking at a fairly expensive flasher unit. (my 91 celica flasher unit was £30+ IIRC).