Adding A Rear Fog Light To Our 1969 MGB Roadster
Rear lights replacing the right hand reversing light on our 1969 MGB Roadster
Rear fog light options:
Halfords have always sold a fog lamp that hangs from the rear bumper but I dont like the look of this and wanted a less obtrusive one. Like all MGBs ours has a pair of rectangular reversing lights in the rear panel. These are lit by 21W festoon bulbs (the same rating as fog lamps and brake lights) so my initial take was to trim a piece of red lens so that it fitted inside the clear reverse light lens and wire in a separate switch.
While technically this worked, the red light produced was only about the same brightness as a side light and not strong enough to work as a fog light. I then fitted a rectangular fog lamp from Halfords, which used a standard 21W bayonet bulb. This sat proud of the bodywork and ended up at too much of an angle and didn't look right with its big black plastic surround. Searching the Internet I came across a company selling fog lights for trailers and they had an LED fog light about 80mm square with fixings 50mm apart, that was fairly flat.
LED fog light installed:
One was duly ordered and it fits perfectly.
It came fitted with two bolts which are slightly larger than the ones for the reversing lights. The light unit appeared to be sealed and I couldn't get in to it to use the narrower bolts from the MGB's reversing light so I just drilled out the captive nuts a little and used the washers and nuts supplied with the light.
I made up a rubber gasket to stop rain leaking behind the light and getting into the boot. It is slightly larger than the reversing light but not much and looks almost like it was meant to be there.
Having LEDS rather than a normal bulb it is very bright and should take very little current.
Fog light switch:
MOT rules for fog lamps say they must be wired in so they only come on when the headlamps are in use and they must have a tell-tale light on the dashboard. Not wishing to drill two holes in the dash I found a chrome toggle switch at Maplin's with a red LED built into the end. This wired in easily enough taking a feed off the headlamp circuit, running one lead to the fog lamp and another lead to earth. The chrome switch looks fairly period and the red LED is suitably obvious when switched on.
Overall an easy and worthwhile modification to an MGB Roadster that is used in all weathers.