just like to know when the engine is running are you supposed to get the voltage increase through out the whole electrical system or just to the battery, for example the isc voltage with ignition on is just under 12v but with engine running its over 13v or the coolant temp. sensor when disconnected the voltage is 4.6v with ignition on and 4.95v with engine running, thanks.

You should see between 12.5 and 14.4 throughout the system, closer to 13.8 when the engine is running.

yep, i get 13.6v at the isc, thanks.

when i wire leds into the car, i do it from 13.8!

Cheers