Tail light not working

Hi All,

My nearside tail light is not working but the brake light is. So the bulb is not at fault. I have checked the connector and there is no corrosion on the pins or contacts. I have also checked the contacts with a voltmeter and got a reading of 6V last week and then 10V when I checked it again at the weekend. I don't understand why this would not cause the bult to shine dimly. I have checked the earth point and it looks as new. However the floor under the carpet is wet. (I also have the wet cubby box problem, new doorseals or drain holes does not solve the problem).
I have checked the fuse and get 12V over the fuse connection.
Can anyone give advise of the cause of this voltage drop or a solution?

yer brake light/tail light bulb is tha same wun....it b a double filament bulb.

Yes thats why I am confused. I thought it was the bulb at first so replaced it but still no joy. So have tested it in the offside and both the brake and tail light filaments work. So the bulb is not the problem. I can't understand why I have a low voltage at the tail light contact.

trace yer tail light +ve all the way back, sounds like ya got a loose or earthing connection sumwhere. how far back can ya trace yer tail wiring harness....must b a connector somewhere after yer fuse box

try disconnecting the tail light completely and then test using an alternate power source

Thanks Bushtoy, There should be a connector behind the bumper for fitting a tow bar but other than that the wire looks unbroken on the wiring diagram to the fuse box. I'll strip off the bumper and see what I can find.

check the connections to the tail light unit, they're prone to water ingress and corrosion.