Took the washer tank out today, the windscreen washer pump filter was nearly completely blocked with black slime, and the inside of the tank was covered with it too.
The tank's shape is a right PITA! You can't jetwash it out!
I tried soaking it (for a relatively short time) with diluted acid wheel cleaner, then washing up liquid, then floor cleaner, then bleach (I think, it said 'anti-biofilm' on it) which was in it for the longest period (~2hrs I think). The floor cleaner seemed to shift some of it, but none of those products shifted it fully. In the end I put the tank back in as I was running out of time.
Anyway, for the time being pump runs just fine now and I cleared the code and it didn't come back. So I guess the BCM (JBE IIRC) does have current sensing, and shuts the pump off after detecting an excessive draw. Would be nice to know for certain, but they you have it.
So, does anyone know how to shift that black slime?
2 people suggested bicarbonate of soda to me, left to soak overnight. Anyone tried that?
Also, anyone know how to stop it sliming up again? [edit] Oh and of course I always use screenwash additive.