JDM Legacy Rear Fog Light Modification

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In Japan, rear fog lights are not a legal requirement and so cars built for the Japanese Domestic Market (JDM) do not have them fitted. In the UK all cars registered after 1979 are required to have at least one rear fog light by law, and the car will fail an MOT test if one is not fitted.

Most importers will bolt a simple rear fog light under the rear bumper in order to comply with UK regulations and register the car. This can look a bit untidy, but thankfully there is a modification that can be made to the Second Generation Subaru Legacy Touring Wagon (model code BG) which will convert the rear light bar to work as fog lights without an unsightly aftermarket unit bolted to the bumper.

Note: I am told this modification can also be used on the Third Generation Subaru Legacy Touring Wagon (model code BH), but as I do not have access to one of these cars I am unable to verify this.

How The Modification Works

JDM Subaru Legacy BG rear light cluster. These differ from the ones fitted to UK-spec cars as they are not fitted with rear fog lights, which are a legal requirment for car registered in the UK.

JDM Subaru Legacy BG rear light cluster with the tail lights switched on. As standard, both the inner and outer lights are lit on JDM cars, but are not at full brightness.

JDM Subaru Legacy BG rear light cluster with the brakes applied. Both the inner and outer lights are at full brightness.

The modification will allow the inner lights only to be switch operated and work at full brightness to act as rear fog lights. Operation of the outer lights is unchanged by the modification so continue to operate as tail and brake lights as normal.

With the fog lights switched off the inner lights continue to operate as standard, working as both tail and brake lights, and thus keeping the original JDM look.

Wiring diagram (Tailgate)

When fitting the relay, make sure you cut into the brake light feed between the junction for the centre high-level brake light and the junction for the near-side brake light. Otherwise either the centre brake light will come on with the fog lights, or only the off-side will work as a brake light.

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