If you don't ever look for leaks or see any obvious signs of water ingress, the first thing you will
probably know about the problem is when the car goes mental. Water gets into the electrics
and cause problems such as the wipers not stopping, the horn not working or working when it shouldn't,
the gearbox playing up, headlights flashing or not working, unusual lights appearing on the dashboard etc.
The worst problem is that the car just will not start.
Generally this means it is time to get a new SAM unit which isn't cheap and unless you have the
leak fixed, it will soon happen again. You could be throwing money away.
Firstly, I don't suggest sticking it in the oven, or using a hot air gun on it. Depending on your talent...
Disconnect the battery and
Don't attempt to dry it in the car.
You have 3 sensible options to removing the moisture.
Try gently heating it up evenly with a hair dryer on the lowest setting,
This should evaporate any moisture inside.
Stick the SAM into a pillow case and zip tie the end closed.
Place it in a plastic bag with a load of uncooked rice and seal the bag.
Place this in your airing cupboard or in a sunny place for as long as you can.
The water should evaporate and be drawn out and held in the rice.
The best way is to open the SAM unit casing, clean the PCB with electrical cleaner spray,
Visually check the PCB for water damage and corrosion before putting it all back together.
Refit and see if that has helped at all. Now try to find the leak that caused the problem.
Leaks And The Problems
If your wing mirror seals leak you can look forward to soggy speakers which don't
tend to work for long, plus the door card fabric can suffer badly from water marks.
Roof seal leaks can drip onto the seats which again cause water marks and are very hard
to dry out due to the expanse of foam used in each one. The first sign is a wet bum.
Boot and rear window seals on the coupe have been known to leak too but not as common,
this can fill the boot with a nice hidden puddle causing damage and a bad smell before you realise.
The bulkhead leak is a tricky one as you can't see it and the ingress area is big.
During manufacture, the bulkhead between the engine and the cabin is well sealed
using an automotive mastic product, this is common on many makes of car. The problem
occurs because smart sprayed the tridion before the sealant had a chance to dry and as a
result the sealant is partially washed away or displaced.
The scuttle tray leak is the one that does the most damage.
Under the windscreen wiper motor is a plastic tray, this is mirrored on the other side of the car with
the air inlet tray. The drain ports very rarely get blocked so it's unlikely that the tray will fill up. The problem
is that the seal used between the wiper tray and the body is very poor at stopping water. It's a closed foam
rubber strip but it's not under much pressure and has been known to move out of its seating channel.
Water running over the top of the scuttle tray seal would normally drip into the footwell but due
to the amount of wiring in that area the water almost always ends up running down a few wires.
To make matters worse, one of the lowest points is the SAM unit (fuse box). The water obeys gravity
and drips into it causing a host of electrical malfunctions. Once the SAM unit is water damaged, the
only option is to replace it at a cost of over £400.
Replacing the SAM unit is just delaying the inevitable, without the leaks fixed,
the new SAM unit will fall foul of the water again.