Originally Posted by drivesafe
OK folks and first a warning.
NEVER, NEVER USE A TEST LIGHT INSIDE any new vehicle.
If you have the ignition on and touch the wrong wire, you can trigger the safety air bags.
This has happened heaps of time here in Australia and there have been a number of deaths caused by this practice in the USA.
If you want to check out your trailer plug at the rear of the vehicle, fine, but under no circumstances should you ever use one anywhere else in or around a modern vehicle.
Next, the cables ( WIRES ) in the 12S ( WHITE ) plug are next to useless. They are way to thin and will cause heaps of voltage drop.
The RR has 3mm2 “WIRES” and from memory, the D4 might have 4mm2 or 6mm2 but both are still to thin.
If you have a low 100Ah battery, it can pull as much as 35+ amps, add another battery and !
The wiring is so thin that it is only barely able to top off a near fully charged battery.
Minimum battery cable size over that distance is 6B&S ( 13.5mm2 ) or 16mm2.
The fridge wiring is suitable for a compressor type fridge or the very smallest 3 way fridge.
Last but not least, the wires are ignition switched on a D3 or 2.7lt D4 and Motor ON switched on a 3lt D4