Weird electrical problem with my 2003 Xsara 11

[scubaman66]

Resynched the immobiliser today (many thanks to Bobins who kindly drove over to plug his Lexia into the car) and the car now starts and runs great. It now, however, seems to have developed an electrical fault which is causing the following:

All the switch lights on the dash no longer work
The car seems to be stuck in Eco mode so no A/C, elec windows, Radio, Central locking
No lights, wipers, indicators
Gauges (speedo, tacho, fuel & Temp) all work when you start the car but when you turn the wheel they randomly stop working (at the same time the engine check light and brake fluid light flash on and off again once). Turning the ignition off and then restarting the car resets them until turning the wheel again.
Driving the car a few yards caused the same problem and also brought up the battery light.
Both horn and cigar lighter work fine
Brake lights work

Diagnostics done so far:

Lexia says 'positive feed missing' (I think that's correct - forgot to write it down)
All fuses seem to be fine (in dash and under bonnet)
Alternator charging correctly (14.4v across battery terminals at idle)
Battery showing steady 12.9V with all switched off (ditto with ignition on but engine not running)

This car is going to give me a nervous breakdown.

Any help would be gratefully received.

[scubaman66]

**** FIXED ****

Don't know what made me go and check but discovered that there was some surface corrosion on the SHUNT fuse. Gave it a quick wipe with a Scotchbrite pad, put it back and was greeted with a 'bing bong' chime and everything lit up. Quickly went through all the controls and now everything works as it should. RESULT!!!!

[miked]

I'll remember this, in case it happens to me. I also have an '03 Xsara.

Was the 'SHUNT' fuse one of the maxi fuses under the (BSI) fusebox?

[scubaman66]

It's in the dash fuse box - it's marked SH and sits between F5 & F6 shifted towards the centreline of the fuse box.

Was obviously allowing a small, intermittent current flow but not enough to work correctly.

Car had been sitting since October so obviously condensation had got to the fuses. Going to pull them all one by one tomorrow and give them a quick clean up just to make sure there are no problems in the future.