Lights blowing fuses

[Jim A]

Hi.

we’ve spent today trying to solve some electrical problems on my Mk1 GT6. Any suggestions on where to look next or common problems gratefully received.

Symptoms:

Fuse 2 blowing and whips of smoke coming from fuse box. Rear lights and number plate light not working.

Fuse 1 blew once but was initially ok when replaced. Brake lights not working even when fuse ok.

Found nothing conclusive. Some work with the rear light back plate seemed to improve it. Rear lights worked but at times were very faint. That seemed to resolve with some more work to the light backplate. 

Rear lights seemed to resolve with that (not entirely sure what the cause was). Brake lights still not working.

Top fuse blew 3 times in half an hour after the work. Rear lights are now ok. 
 

One other anomaly. The headlights mate either dip or main. No side only option.

 

More work to do. Any thoughts? 
 

thanks

Jim

[Clive]

8Lights not working is often down to poor connections. Undoing connectors, a rub with something abrasive and put back together often fixes them. But doesn't explain fuses blowing. That can be a short circuit or damaged wiring  so can take some finding. 

Do have a look at the wiring connections under the nose of thd bonnet, a regular problem area. As indeed can be the loom to them from the chassis.

I tend to spray some protective wax on the connections to help prevent further corrosion, but only once everything is working as it should.

[Matt306]

Something is shorting to earth somewhere along.  I would take bulbs out and check continuity on the positive feed line to earth . When you have found the positive with the continuity to earth you have your wire to trace back

[mk2vitesses]

When faced with a shorted or grounded power feed, I found soldering a lamp across the blown fuse (eg 18W) then disconecting the wires to their various locations worked well and gave a visual indication when the short was cleared.