When you say the wiring seems OK, does that mean that you've checked with a
voltmeter/test lamp that you are getting juice at the relevant connections -
or just that it looks OK?
First job is to go through methodically with a wiring diagram and a test
lamp or voltmeter, that should lead you to the point where the connection is
If you are getting voltage at the connector, but the bulb isn't working, you
might have been unlucky enough to have two duff bulbs. More likely,
however, there is a connector somewhere with a weak connection - just enough
electrical contact to light a test lamp or activate the voltmeter, but at
soon as you try and draw some serious current the high resistance at this
dodgy connector results in massive voltage drop. This sort of thing can be
a bugger to track down, 'cos you don't get particularly useful info from a
test lamp approach. However, since the main beams are fine at one bulb, the
dodgy connection must be between the good bulb and the bad bulb, so there
can't be too many connectors, just take all the connectors apart and give
them a good clean so you've got nice shiny metal - could be all you need.
You could try tracking down the dodgy connector with the lights switched on
and the headlamp connected on the bad side, then you will get a low voltage
everywhere downstream of the bad connection, BUT the bad connection will
probably be getting very hot when you do this, and you don't want anything
to melt! Then again, the release of smoke may help you locate your bad
Hope this helps!
Richard & Nancy ('73 Black Tulip BGT, slowly awaking from 11-year
This email and any attached files are confidential and copyright protected. If
you are not the addressee, any dissemination of this communication is strictly
prohibited. Unless otherwise expressly agreed in writing, nothing stated in
this communication shall be legally binding.