Headlight problem

[rawiz]

Hi. I’ve got a headlight issue. Just one Wagner headlight (passenger side) suddenly not working, either dipped or full beam, pilot light is on OK though. Other headlight fine. Faulty one appears to have full voltage across the pins (maybe not enough current though?). Swapped the Wagner over so isn’t that (and old one works when switched to other side). Any suggestions, earth perhaps (where is it)? All other electrics and rest of car working perfectly I think, polished up all the earths I could find back when I first bought it).

P.s. it’s a 1971 lotus Europa S2 in Bahama yellow, in the UK, RHD.

[dakazman]

Hi rawiz,
  S2 uk print
http://www.lotus-europa.com/manuals/misc/electrical/s2-diagc.gif
 
Follow the black wire from your headlights to the diagram. I’m assuming it’s not a tc . You may want to blow this up and mount to a 2’x 3’ poster.
Dakazman

[jbcollier]

If you have voltage across the headlight connector it means you have a ground issue.  Disconnect the headlight connector and test for power.  That's your headlight power feed.  Hook the connector back up.  The other wire that is now powered is your ground.  Jump that to ground to confirm that's the problem.

Now get a wiring diagram and go through each connection on the ground circuit until you find the problem.  There is a connection at the other end of the headlight "pigtail", then near/at the rad fan relay and then back to the dash support to chassis (if I remember correctly, check the diagram to be sure).

[rawiz]

Apologies. Not fully understanding that. Just tried connecting a flying earth lead to the battery negative from the Wagner earth but that didn’t work. I’ll try one of those bulb screwdriver flying lead things to see if current to light that. Plus check my flying earth ok with a multi meter!

Can’t yet see where that headlight connects to the dash earth bar. Kind of assumed it would be near the switch and the same as the other headlight. Pretty tight around there. I’ll have to adopt the lotus position and have a closer look.

The headlight wiring all seems very neatly bundled up as it comes back to the dash. All other light working that side too. Sigh.

[jbcollier]

Disregard the colours:

http://forums.pelicanparts.com/uploads23/H+4SocketDiaJadams1pic11961569061409336403.jpg

Disconnect the connector from the headlight.  Test with an incandescent test light.  Which connector has power?

Hook the headlight back up.  Test with an incandescent test light.  Which connector(s) has power?

Report back.

[rawiz]

Will do. Probably tomorrow. Think the middle pin was earth on mine? Varies model to model?

[jbcollier]

It is a 7" headlight then the connector is the same regardless of whether its tungsten or halogen powered.