Thread: Waterproofing the Puma Brain Box Under Drivers Seat

I have not water proofed my puma (2012 90) and do not have a 'snorkel' and ive had mine in about 1 mtr of water, moving with a decent bow wave, ive also had it sitting in watter more around 700mm so above the recommended wading depth, only ill efect was yes water int he 'brain box' which causes my rear wiper to move on its own accord untill I pulled the fuse, dried the box out replaced fuse. . no further issues (that was ages ago, Mulgo ex-box is the best solution and I will fit one when I can afford it)

Brains are no longer under the seat. The ECU is at the rear of the engine bolted to the head. I'd expect it's sealed quite well to live there.

I'd be more worried about corrosion in the wiring loom if you get water into the seat box. A good spray of Inox will stop that.

Even on 2008 Puma, the ECU is in the engine bay... what lives under the driver seat?

Under the seat is abs/ tc and fusable links, relays and the like. Mulgo make the exbox which moves all of the electrics to under the cubby and frees up the space under the seat for storage or a compressor or both.

Best bit is that it raises the cubby to a good level to be an arm rest.

The engine management computer is mounted on the firewall directly behind the motor on all PUMA models.

There are various electrical systems, fuses and wiring junction points mounted under the drivers seat. The most crucial is probably the ABS unit.

Mulgo's X-Box is a simple and well engineered solution. And free's up the seat box for storage.

The other crucial electrical element is the fly-by-wire throttle sensor, above the accelerator pedal. A small amount of water will disable it and no more throttle.

Originally Posted by chook73

........................ Mulgo make the exbox which moves all of the electrics to under the cubby and frees up the space under the seat for storage or a compressor or both.

Best bit is that it raises the cubby to a good level to be an arm rest.

Originally Posted by Drover

......................Mulgo's X-Box is a simple and well engineered solution. And free's up the seat box for storage............

I also recommend the Mulgo ExBox for the reasons mentioned above. There's a lot of space under the seat which can be put to better use.

Cheers, Murray

Hi Drover, I'm assuming if you keep enough of a bow wave the interior and throttle pedal sensor typically stays relatively dry. If they do get wet is it a simple case to let them dry out on the side of the road?

When I first got my car, I sealed up all the gaps in the panels of the drivers side seat box with sikaflex and then large amounts of underbody spray on the outside. After 80,000km the box is still dust and water tight. I took my Defender through Nolan's on the OTT when I first got it, water was over the top of the bonnet and a bit came in through the door seals ( I fitted the new style ones) but the drivers seat box stayed completely dry.

I thought about making the top cover of the seat box water tight, it would take a decent gasket, lots of screws and a new cover but I think it would be possible, but since the top of the seat box is around the same level as the throttle sensor, I would not be going anywhere.

The advantage of moving all the gear to the X-box is another three inches off water before the various other bits get wet.

I was working on my auxiliary electrical system yesterday, the battery box under the passenger seat has some very large gaps which I sealed up last night. One seam had a 8mm gap and now I have a few circuit breakers, battery monitor shunt, solar regulator, dual battery control system etc so it is worth waterproofing that as well. Both batteries have vents which go outside the box, so there should not be any hydrogen build up.