Triumph Repair: No low beam but have high beam on headlights, Triumph, Spitfire

Question
Hello there. I have a 1978 Spitfire and my headlights dont work on low beam but they work on high beam. What do you think could be the problem? Thank you for your time and help.

Answer
John,

Power for the headlights goes directly from the battery to the headlight switch, then to the dip/flash switch on the column.  

The fact that the high beams are working but not the low beam says the problem is somewhere between the switch on the column and the headlights.

Either the switch has failed, or there's a broken wire or open connector in the wiring harness.

The wiring for the low beams is a blue wire with red tracer.  Check the wires coming off the steering column with a voltmeter to see if the problem is with the switch or the wiring forward of the steering column.

If you have power at the connector harness coming off the switch, then keep working forward to find the open circuit.


Cheers,

Jim