I have a rear fog light warning which comes on and off at different times.my right rear fog light is working.not  sure

if left light should work or not.

As standard only the offside works but IIRC the nearside can be programmed too.

Why does the warning come up if the driver side fog light is working.

This is a 2009 Octavia ambioce

It may be a dodgy bulb or connection. Try reinserting another bulb and see how that goes.

12 hours ago, Smileyb said:

Why does the warning come up if the driver side fog light is working.

This is a 2009 Octavia ambioce

Have a look at the contacts and give them a clean, sometimes the bulb warnings come up if it detects even a slightly off resistance value.

13 hours ago, Smileyb said:

rear fog light warning

Do you mean the "rear fog on" telltale, or the bulb failure warning?

Removed light cluster in the rear and swopped them around with one on right side.

I still have the same problem in the left hand light.

I do not seem to have a voltage at the rear fog bulb on the left.

Would this model only have a right rear fog lamp and if so why is the left fog light warning coming up on the dash 

 

22 hours ago, Smileyb said:

Would this model only have a right rear fog lamp

Don't know, because you've not filled in the "Location field" in your profile so I don't know if your car is right hand drive or wrong hand drive. However, EU cars normally only have a driver's side rear fog.