Strange Headlight Sequence Issue Mazda BT-50

Hello,

My 2010 Mazda BT-50 (1st Gen with 3.0L turbo-diesel MZR-CD) is having a strange headlight sequence Issue I can't easily solve.

• When turning the headlight dial on: right headlight and parking light turn on, left headlight remains off, left parking light on

• When turning on main beams: right headlight turns off, right parking light remains on, left headlight and parking light turn on

i.e.

• Headlight to ON: RH Head + RH Park + LH Park

• Main beam to ON: RH Park + LH Head + LH Park

All the fuses/relays look good and I can't see any obvious wiring faults but I'm not particularly experienced. Has anyone experienced this kind of issue before? Any advice would be greatly appreciated.

The lights worked normally 3 weeks ago during a roadworthiness check.

Thanks!