Switched 12 v source

[Entwood]

Due to yet another the failure of the "sensing relay" that feeds the towbar wiring I'm going to fit an "old fashioned" "switched relay" instead.

In the old days I used to take a feed from the alternator output to control the switching, but rather than delve down at the alternator socket, is there an easily accessible "switched live" in one of the additional fuse boxes by the battery

Should be 0 volts with ignition off, less than 4 volts with ignition on but engine not running, and greater than 12 volts when engine running, but I suppose 0 off, > 12 on would suffice.

I'm useless at reading wiring diagrams the way they print them nowadays, so if any electrical wizards out in OOF-land could help it would be greatly appreciated

[Kevin Wood]

Here's an idea. Why not connect the feed via a relay that's energised by the fuel pump circuit? It's only live when the engine's running (ECU controlled) and the wire is conveniently close to the tow bar electrics.

Kevin

[Martin_1962]

The thick cable is switched and I use that as my switching and solendoid feed with a thicker fridge cable

[Marks DTM Calib]

Heres an idea

Remove the wiring and tow bar then set fire to the pikey wagon  

[Kevin Wood]

Heres an idea

Remove the wiring and tow bar then set fire to the pikey wagon