1971 Satellite Tail and Parking Lights Fuse When Ignition Is On

[RRChris]

This one is starting to drive me crazy.
With the ignition off (car not running) the parking / tail lights work without blowing the cigarette lighter fuse (which is the feed to headlight switch B2). The car can sit for over half an hour with no issue.
However, with the car running the fuse blows within a matter of minutes.
I have checked the continuity in the parking light / tail light circuits (with all globes removed) and with ignition off everything tests OK. The circuit has been previously modified to only feed the B2 circuit on the headlight switch (no feed to cigarette lighter or map light on dash).
With the bulkhead connectors and the battery disconnected and with the ignition switch on I seem to get continuity between #10 (parking lamps feed) and #23 (ignition run) on the bulkhead connector. Do I have a short or am I missing something else in the circuit that would do this??
Anyone with experience of similar problem? Is it possibly the #1 splice joint?

 

[tak419]

You have a short or someone has wired in something you're not seeing. I would take the harness out from behind the cluster and see what it looks like. Look for repairs or an area that is pinched or rubbing thru. Previously modified you say ? Good luck.

 

[RRChris]

Thanks mate. I thought that was what I was in for, just wondering if I missed something simple.