the the electric current as a highway from one side of the battery to the other.
on the highway, cars drive with a bucket in the back. in the bucket are volts, a full bucket is 12V and an empty one is 0V.
the highway goes from the + terminal to the - terminal but on the way it goes trough many stations.
after the start, they go trough the voltage regulator to check the bucket is not too full or too empty.
after that, they go trough the fuse box. if there are too many cars on the highway, the fuse burns. burned fuse = blocked highway.
if the fuse is ok, they go trough a wire to your device. for exampe cruise control but that can also be a light. doesn't matter.
at the device the drivers empty their bucket on the back seat but they still continue driving to the negative terminal of the battery.
so you can measure 2 things:
current (in Amperes or Amps), that is how many cars pass trough.
and
potential difference or Voltage (in Volts), simply how full the buckets are.
If your device is using power, it needs both current and voltage. since electric power is simply voltage x current.
no voltage, no energy.
no current, no energy.
no matter where you measure in a closed circuit, everywhere there is the same traffic. so if you measure before, after or in a fuse, current is the same.
so if a device is off (or should be off) you measure 0 Amp. simply no traffic on the highway.
http://www.uk-polos.net/view ... 72#p497935
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... 
no problem, revert to the previous state and ...
(to install a steering wheel of the new model 
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