So I thought I may as well do a post with an update on my sportbrake CJB removal and washer pump replacement in case it helps anyone else out in the future. I followed the advice from here regarding unlocking the car and leaving it 15 minutes before disconnecting the battery and removing the CJB. I had the CJB out and back in and I've had no problems at all and it required no programming.
You can see here the corrosion inside the connector on the CJB.
I had the CJB apart to check the board in more detail, everything looked good and the corrosion on the pins cleaned up quite easily so I think I have been lucky.
I replaced the pump and but a bullet connector break in each wire from the pump in the wheel well. I didn't take a photo of this. I removed the washer pump pins from the plug in the footwell.
The blue/white and green cables are the washer pump wires, I gave them a clean before reinserting them back into the plug. Interestingly, the worst cable was the green/white cable in the pin above the washer pump cables. You can just about see in the picture that its very green inside the pin, and its actually the corresponding pin on the CJB that is corroded
NOT washer pump cables. I could not see any green/white cables coming from anywhere on the washer bottle so I don't know what this cable is for but it goes against the 'water tracking from the washer pump' theory 🤨
However, I cleaned it up and put it back in the plug.
While I had the washer cables de-pinned, I spliced in a 'water break' for want of a better word. My friend suggested the idea of un-sheathing the cables to allow any water tracking inside the insulation to escape in a 'drip loop'. The pictures below hopefully explain what I mean. The cable is unsheathed, looped into a U then a heat shrink sleeve put over it to protect the conductor but allow water to escape (obviously have the opening pointing down).
I spliced these in to the washer pump cables, re-pinned the plug, installed the CJB, plugged everything back in and......washer fluid level low pops up still! 😞
I now think that the washer sensor needs replacing, all of the plugs connecting to the washer bottle were soaking wet. The plug for the fluid level sensor was the worst.
I did give all the plugs a good scrub with a toothbrush and IPA and they all got a coat of a water displacing electrical film but it hasn't helped. So I will be ordering a new fluid level sensor shortly.
I'm not too annoyed as I know I have done some preventative maintenance to hopefully stop any future issues of corrosion in the CJB.