Hi all,

I had done a bit of searhing on here and found a few answers to my issue but no solution for sure.
I have a TL AWD Magna and last week i noticed the drivers side brake light was out. Righto thinking its just a globe i put a new one in (but didnt check it was working, just presumed).

This week I noticed my cruise control was not working and then reading on here i found its linked into the brake light system. Ok I find now i have no left or right brake light but do have the high light on ok, and no lights when the headlights come on at the rear (the second filament in the globe) .

I thought i had blown the fuse and changed this, still nothing. So i check the globe and find i had not 'clicked' in the globe all the way into the holder. Then the headlight on was ok, and the passenger side brake light was ok, but still the drivers side was not. I am sure the globe is ok as i switched then from side to side and on the passenger side it was working fine but not back on the drivers side.

So this brings me to assume i have a bad connection somewhere, but not being that electrically gifted i have no idea where to start the fault diagnosis, any help would be greatfully recieved.

Will the cruise system require me to find this fault before it comes on again (i have not been out to test it yet)?

Sounds like you are not correctly installing the light bulbs - they are offset bayonets and if forced in till they click (from your post) this indicatres you may have them in the wrong way. The bulb will easily slip in and rotate to lock if done correctly and if not then you can cause anything from dead shorts to feeding power into other circuits etc.

I am able to run the appropiate tests if needed to try and determine what is going on here, can be several simple little things or may be a little more serious, either way issue seems to be in the back end of the car if the top light is still running

thanks for the advice, will look your place up if i cant figure it easily


Sounds like you are not correctly installing the light bulbs - they are offset bayonets and if forced in till they click (from your post) this indicatres you may have them in the wrong way. The bulb will easily slip in and rotate to lock if done correctly and if not then you can cause anything from dead shorts to feeding power into other circuits etc.


To my way of describing them they are not bayonet fittings, they are solid glass with double contacts on each side in matching locations, so it appears impossible to put them in the wrong way round as the contacts will always meet at the same location. (To me a bayonet globe has two prongs on a circular metal base, these dont they are a glass slot with four contacts, two per side)

It also does not explain why when flip them over in case their is a right / wrong way that the headlight illumination works perfectly but the brake light does not in each configuration

thanks for the advice, will look your place up if i cant figure it easily




To my way of describing them they are not bayonet fittings, they are solid glass with double contacts on each side in matching locations, so it appears impossible to put them in the wrong way round as the contacts will always meet at the same location. (To me a bayonet globe has two prongs on a circular metal base, these dont they are a glass slot with four contacts, two per side)

It also does not explain why when flip them over in case their is a right / wrong way that the headlight illumination works perfectly but the brake light does not in each configuration


You are correct and my apologies for giving the wrong info - I do so much work on the daughter's Commodore that I get the two confused sometimes.