Glad you take it in the sprit which it's intended

How long was the power lead and the size? Sounds like you sliced into an existing 12v supply and if the cable wasn't excessive in length (couple of metres or so?), then i would have expected that if the cable had chaffed to the body the fuse would have blown provided the splice was good. Body resistance is very low.

However, if the short circuit occured within the unit itself, then the earth path comes into it.
As it sounds as if this possibly a small cable size, this could be the cause of your 'themal event'.
Is the earth cable also damaged by heat? Another member of the failed FL2 clutch/DMF club, twice.

yeah, both earth and power were part of the thermal event.

The wire I used to extend the power source was a 14 AWG and it was soldered at the splice point. Connected to the boot fuse box with an empty slot.

 Cuatro Por Cuatro

It's not cable chaffing, otherwise the ground cable would be okay.
It's one of two things, either too high resistance caused by incorrect cable size/long length or the unit itself is faulty.

To help you, i know from experaince that 2 meters of 0.5mm CSA cable shorted direct to ground will blow a 10A fuse to smitherines. Another member of the failed FL2 clutch/DMF club, twice.

Thanks pegleg.

The power run would be just about 2 meters. I had the fuse in line at the power source so I am just guessing the unit was at fault. (Te remove any blame from me, ha ha)

As you can imagine I am a bit scared by the whole situation so no more aftermarket electronics for the LR  Cuatro Por Cuatro

No problem.
Can't help thinking how many of thses things could cause a hazzard to others. Another member of the failed FL2 clutch/DMF club, twice.