Outer Limits 4x4 Board

as the title suggests all my lights (head ligh interior etc) pulsate when the are on. It is quite notecable, and seem to be getting slowly worse. It pulsates alot faster the higher the revs. Does anyone have any idea what could be the cause of this, i was told maybe the regulator, but how do i chech that. also i don't think the alternator is charging the battery properly as it takes ages to charge a battery and the multimeter only reads about 13 volts across the battery. Oh yeah it in a rangie, but i think it is a ford alternator as it has ford written on it, it's certainly not a land rover unit.

Check the voltage at the battery again while reving the engine and see what it comes to.

check all your earth connections. we get this prob in BMW's a bit at work. it causes the alt to do funny things.

yeah i might check the earths cause they do look pretty average, yeah ill have to check the voltages but can't at the momement cause i pulled a rocker cover off and ran out of gasket goo to do the plenum chamber. But thanks for the help guys, really apreciate it.