Waterproof cover for fusebox

[rosie]

My '92 GTII has a persistent problem with water leaking into the passenger footwell. I've had a new windscreen seal, drilled extra drainage around the blower motor, spent many hours trying to work out how the water's getting in, and still it keeps coming.
It's had 4 new fuseboxes over the 6 years I've owned it, each time the water has corroded them, even though this time it hasn't felt wet round the fusebox since I resealed the windscreen, there are telltale signs of water damage yet again.
I've got loads of electrical faults and a mechanic who says the wiring is getting so hot that he feels it's too dangerous to drive. :(

I remember a couple of people saying that they'd made a waterproof cover for the fusebox, which had prevented this seemingly very common leak. Please does anyone have any advice on how to make the cover, and whereabouts exactly they fitted it? I have minimal knowledge and skills so layman's terms would be appreciated please!

I'm at the end of my tether, and worried about using up the world's supply of secondhand fuseboxes. Don't want to fit another new fusebox without some means of stopping the water getting to it again.

[go-for-it1]

What do you mean "drilled extra drainage around blower motor"

[Nate]

^^what he said

I've mentioned this before, but have a looky up inside the plenum (you'll need a mirror and torch) and look for signs of rusting thru. Easier to see from inside with the dash removed, but that means removing the dash. Fuse boxes ain't meant to be service items!

[Jack92]

Guessing you have already but seal around where the wiring looms come through from the engine bay, had this problem on mine.

Another issue I have seen once before but it was oil not water, was it being inside the Shield on the cable. Very strange I know but it turned out the pressure sensor had failed and oil was getting pushed right round into the ecu.
This wasn't a scirocco however but may be worth some investigation if you can't find the source anywhere else

[Village Idiots]

I found that you can get to the fusebox and the tin work above it to check for corrosion/leaks by removing the glove box.....the lid, then the whole box assembly. I waterproofed my fusebox (I did cure the leak by using sikaflex round the windscreen seal, glass and metal sides) by glueing a piece of plastic ground sheet to the metalwork above the fusebox, so that it hung down the back and front to divert any water past the box. Bit tricky at the back with the wireing, but can be done. Be generous in the sizing.

[rosie]

goforit1 and nate - the holes I drilled are under the bonnet, under the rain scuttle. Water was collecting around the blower in the centre, so I drilled a couple of holes to allow the water to drain out straight onto the road. The other drainage holes were clear but the water was collecting anyway.

"have a looky up inside the plenum (you'll need a mirror and torch) and look for signs of rusting thru." I'm not sure what a plenum is but I'll try to work it out. I've removed quite a lot of the interior plastic shelves etc around the fusebox looking for the leak, including the glovebox. But I've never been able to get the central console out.
The original leak I had was in the corner above the fusebox. The windscreen seal was at fault. This was fixed and as far as I can tell no water is getting through there anymore. I thought that the fusebox had been dry for the last year but my mechanic thinks otherwise. The annoying thing is that I haven't found any sign of water coming in over the fusebox since the windscreen was resealed. I thought that if I made a cover for it I could stop worrying about the fusebox and concentrate on finding the big leak.
I'm going to try the groundsheet idea.
The water seems to be coming in behind the central console, which is why I thought that the blower motor might be responsible. But I can't get enough of the interior fixtures out in order to properly investigate it.

[rosie]

Nate - I've just seen your other post with an annotated plenum locating diagram :) I feel much better informed now. I'll have a poke around tomorrow, before the new fusebox goes in, and see what I can see.
At the end of that thread someone has suggested running a smoke machine in the car to see where the smoke gets out, and therefore the water gets in. I like the sound of this, and have friends in the disco business, so this might be my next move.

[rosie]

I'm also wondering whether a leaky heater matrix might be an issue. The water is coming in behind the centre console, and I'm getting through loads of coolant. There's no obvious smell of coolant in the car though. Would this rule it out?
Any way to be 100% sure whether it's the matrix or not? (though obviously this wouldn't be causing the fusebox issue, except perhaps by excessive condensation)
Times like this I wish my husband was a bit more handy :(

[Nate]

To rule out the matrix, just disconnect it! Take the 2 pipes off in the engine bay and temporarily join them together

[rosie]

I found out where the coolant is going - my mechanic had neglected to replace a hoseclip. I had the heater matrix cover off and there was no sign of water around it so I'm pretty sure I can discount the heater matrix now.
I had the fusebox out and sure enough there are dried up signs of water getting onto/into it. So I'm back to looking for a mystery hole. Had a look under the plenum (now that I know what it is) and it all looks good under there.
Smoke pellets from a plumbing supply shop and a big tube of pu sealant might have to be the next step.

[ianaudia4]

An even easier way to find where the water is leaking is to use a watering can with water mixed with chalk. Take as much of the dashboard as you can out and get someone to pour the mixture, the chalky water will be easier to spot (unless your car is white).
I used this method to solve an annoying leak on my Scala a few years back.

[rosie]

The problem is that the water is coming in somewhere behind the dashboard, and I can't get any more of the dashboard out of the way without better tools/more brain power. I tipped 8 buckets of water over it yesterday to try and pinpoint the leak and it didn't leak at all, but when it rained today it leaked instantly. I'm at the end of my tether!
I've done this as a temporary measure. My car has a catheter

[ianaudia4]

Removing the dash completely is not a major job and doesn't require many tools that you probably already have. It is just time consuming!
When I solved my leak I had all the interior out including carpets but if the car is your daily mode of transport then that may not be possible.
Is there not a member or two in your locality that you could call upon to assist?

[ianaudia4]

Out of interest does your car have a factory fitted sunroof?

[rosie]

As far as I know the sunroof is not a factory one. Several years ago it was leaking and I think that during my investigations I found it it wasn't standard. I tipped loads of water over the sunroof yesterday and nothing came into the car anywhere, so I don't think the sunroof is the problem.

I think I'm going to have to take out the dashboard, but I've got an MOT on Tuesday which I'm going to fail, so then I need to concentrate on getting those things fixed before I dismantle anything else.
I don't know of any other forum members around here, I think that several years ago I put out the call and no one answered. Met another Scirocco owner round the corner from my house the other day, but when I pointed out that his coolant level was too low he didn't know what antifreeze was, or where you put it, so I don't think he'd be much help.

The Haynes manual has no advice about the dashboard. I've already taken out all the shelves and the glovebox and the carpets so I'm halfway there, but a bit wary of tackling it without any help. Does the steering wheel need to come off?