Thread: Low beam short circuit. did oil do it?

Potentially yes.

That's a bit strange though cos oil used to act as insulator, it has almost no electrical conductivity but it can mix up electronics if it's hot... also according to the diagram there's no fuse within the dim/dip relay, it's a resistor, i presume that the blown 30A one is actually fusible link 1 = 30A, in this case remove it, see which side is live, disconnect battery, set multimeter to continuity/ohm put one probe on the unlive side and one to body if you get continuity to earth we'll speak again if not switch on the lights(yes, with battery disconnected)..if you get continuity to earth this way remove the big relay, if no change remove the headlamp relay if on one's removal the continuity will end there's the problem and we'll speak again

Clean oil is an insulator...

I do agree that SFs methodology to chase the fault is a great idea..

Thanks sierrafery, Just so we're clear on where the issue is, I submit this picture showing the Traxide relay mounted on the inner guard near the power steering container. As you can see one of the 30 amp fuses is missing from it's position to the left of the one remaining. I offer this in case it changes the procedure you've already given me. Also, I don't have dim/dip fitted to my Defenders.
Don.

AAa-ha... i didnt understand from your first post that the fuse from that Traxide unit was blown not the vehicle's fuse...in this case off course that the procedure i described is futile.... the problem might be within that unit and i'm useless cos i have no experience with them nor a diagram ... the gist is that when a fuse blows it's a matter of short to earth or excessive load somewhere ... you can try similary to verify continuity between the unlive side of the blowing fuse and earth while you remove things untill the continuity cedes

I had 2 of these fuses blow for no apparent reason within 6 months of fitting. Not oil but was looking for contaminants or other electrical issues and could find nothing. 6 odd years on have not blown another, so maybe even just an itinerant fault? Or maybe even water ingress at some point.

I've now had a message back from Tim at Traxide to say clean the unit inside and out with dishwashing detergent, then let it dry, as a first step. I'll get that finished tomorrow. I'll try some fault finding with the multimeter after that
Don.

On cleaning up all the mucky oil, I discovered this. It's not reassembled and tested yet, but I think that brown wire was the problem. I've repaired that and threaded it through split conduit to avoid a repeat performance.
Don.