Lighting Fault

Hello, during the summer i installed a Red Bison Boomslang unit to my headlights and its been running just fine until tonight when i noticed my N/S headlight was very dull, so i set about fault finding, all wiring is good an clean still, fuse is good, relays checked and head light plug disconnected, cleaned and reinstalled still nothing until i last resort i disconnected my O/S plug and the N/S lamp returned to full brightness, the whole system is now working just fine, but i would still like someone to explain why encase this is not the end of it....

I can't easily find a wiring diagram for the kit, so I'm left to guess.

Does the N/S earth connect to the bodywork anywhere near the O/S connector? Perhaps it's a bit corroded and you nudged it while fiddling with the N/S plug?

Thanks for the reply, the earth point for the N/S plug is under the N/S wing and everything is well cable tied to the O/S plug so not likely to influence it..

Can you point me at a wiring diagram?

Well it happened again today, so methodically I checked every bit of the wiring with no success, then if by magic once the O/S h4 plug is taken off the lamp hey presto the other lamp fires up to full strength, then I replace the plug and it's working again all day.

Thanks for the diagram.

Was the n/s headlamp dim on both dip and main beam?

Yes it was!

First thing to check is the n/s earth - take it apart and get it back to bare metal. Is the path from that earth point to the battery all sound (If it's earthed to the wing, is the connection between wing/radiator panel/chassis bracket/bulkhead good enough)? Or, next time it misbehaves, leave the lights on and connect the earth point direct t battery negative with a jump lead - see if that improves it.

Thank you, I will try and get back with results.