Towbar Electrics Bypass Relay 12v cable - Help.

[Teedub]

I‘ve just fitted a replacement bypass relay on a Devon Aztec - Boxer PVC and discovered the 12v power cable Is dead at the relay end. The cable is live on both sides of the fuse so fault is somewhere between the fuse and relay.

I've discovered that the cable is exposed along the full length of the underside of the van.
Really rubbish job not secured anywhere just hanging loose.

It’s clear that I’ll have to fit a new cable to power the bypass relay and it would be much easier if I could do this from the leisure battery. My question is would this be possible or is it (as I suspect) a complete no no. TIA.

 

[mitzimad]

assuming ots only powered whilst driving it would make no difference as both batteries are joined by the split charge when running

 

[Teedub]

assuming ots only powered whilst driving it would make no difference as both batteries are joined by the split charge when running

Hi Thanks for the reply. It’s a single wire direct from the battery live terminal so is constantly on. However only draws power when trailer/bike rack electrics hooked up. I believe it’s the power for the indicators/lights/brake lights.