Hi
Ive not owned a B..
But most FIATs have electric PowerAssistedSteering (PAS)
This uses LOTS of power
This power is supplied by the Alternator
The battery is essentially 'storage'
A poorly performing alternator will struggle to keep the battery topped up.. even with the 'charge light' going out ok
I had a punto sporting.. same 1800 engine
It had a dodgy alternator and
the PAS wouldnt work on that until alternator started charging
Being the 'electrical circuit' of the car.. there are various things that COULD be at fault..
however.. lets discuss a basic test
Get hold of a 12volt test meter
Multimeters start at £5..and for this it doesnt need to be posh..
Ok
Check voltage across battery terminals..
Should ideally be over 12v (up to 13.2v)
IF you still have access to the 'jumpstart'vehicle .. even better
Good to measure the battery of that for reference
Ok..
So with car parked.. engine off.. should be @12volts
On a typical fiat.. the battery is well away from moving parts.. but just be wary of radiator fan.. 'fan belts' turning etc.
Start car..
With engine running you should see
@14 volts across the battery
(This extra power is from the alternator)
No alternator power.. you will be back to less than 13v
Do let us know.. Charlie