Electrical fault help please
 

Dear All,
I have a standard 2006 STI PPP Impreza which has a puzzling problem that I would welcome any help / advice on. I have searched numerous threads but am still in the dark.
To give you the background, driving up north (father’s day) in torrential rain the following warning lights came on:

- Parking handbrake light
- Engine emissions management (constant)
- ABS warning light
- And the DCCD green ‘0’ flashes
- In addition the speedo started to oscillate randomly.

At this point I was also on vapour in the tank as I wanted to hold out for the Shell services . When I arrived at the services and turned off the ignition, there was a ‘clunk’ sound from the transmission, later I was told this was normal if the DCCD had gone into ‘safe’. On top of all this my windscreen cracked that same morning and my credit card wouldn’t work!
At the services the following things were changed in the attempt to correct the above.
New 12V battery fitted as there had been severe wear/corrosion on the positive terminal of the old one. Also the ‘BACK’ (reverse light) 15A fuse was replaced as this had blown.
Feeling confident the problem was resolved, I pulled onto the motorway when all the above warning lights appeared along with the same fuse blown. At this point I assumed water had just got in somewhere and was shorting to ground causing the fuse to blow. Incidentally (as well documented already on forums) the ‘BACK’ fuse also plays a part of the feeds to the ABS and DCCD, thus if this fuse is removed the above warning lights come on).
After a relay home and leaving the vehicle for some time in the sunshine, I again replaced the 15A fuse. This corrected everything and I had hoped the problem was behind me. However I am on my 6th fuse (over the last month) and I still haven’t located the fault.

Since this I have taken the car to Subaru for a look and no error codes were recorded. Over this time and noting when the fuse blows I have discovered a pattern and I have found I can now blow this fuse by gunning it around right hand bends. Interesting (to me anyway) and also when taking right hand bends sharpish, I can make the speedo oscillate or stop working completely. Moreover I can get the speedo back again by hitting bumps in the road or by playing on roundabouts. I have also noted that the speedo can completely behave itself even with the fuse blown…
I have ordered a new VSS that I will fit tomorrow having removed the other one today. The old sensor and harness both visually looked in order and all other fuses are ok. I have also disconnected the reverse light switch on the gearbox to see if this resolved things as someone had a very similar issue, but this didn’t help. Sorry for the longwinded background and any red herrings, but these are my facts and it is an odd thing.

So assuming I have a faulty VSS (or an intermittent wiring short):
- How could this blow the ‘BACK’ (reversing light) fuse. Is it possible that if the ECU gets confused from and incorrect signal from the VSS the ECU can voluntarily blow a fuse to place the vehicle in a ‘safe’ mode? I know this sounds mad but I am fairly sure this is what my Subaru agent was alluding to and this would explain my situation?
- Why would RH bends / bumps blow my fuse if the fault is with the VSS?
- Can I assume its is the VSS?

Cheers!!