electrical problem

not had my octavia 1.9tdi long and had 2 probs after very heavy rain, 1 prob may have been due to water ingress but the other i think was to do with hitting a large pothole whilst struggleing to see the road, we went out and lost the speedo, reverse lights at whatever sensor stops the fuel gauge fluctuating when going around corners, so i took it to a garge, there diagnostic machine for some reason wouldnt talk to the car, so we booked the car in to be looked at, we were told it could be part of the loom somewhere and the alternator was not kicking enough volts out (batteylight had started to come on) i rung verious people and looked on websites and only could come up with these capacitors in the back of the dash (older octys sufferd this) not being happy with this as it was only the speedo and not the whole dash, speedo sensor ws fine so i started checking the loom and located the reverse light switch (under the battery tray) i gave all the wires a tug around the reverse light switch part of the loom and hey presto it all started working! so all it was, was a dickie connection, But i saved me garage bills! As for the low voltage on the alternator, i could hear a humming noise coming from the boot, peeling the interior away i exposed the little charger that charges a caravan fridge or battery whilst the engine is running (car has tow bar with twin electrics) after cutting the two input wires the humming stoped and battery light went out! Its all working as it should now, Cuffed with myself as im only a landscaper and hate electrics! Hope this can help anyone