Voltage drop Options

[Dave97]

What is normal voltage drop when you turn on the lights? I’m just going off the volt meter, but I start at about 14.2 driving around, when I pull on even the first notch of the light switch I’ll drop to less than 13. Is it a ground issue? I understand that this a rather common. Thanks. Dave

[davep]

It could certainly be a ground issue. I had a 914 where starting was hard until I added a ground cable from battery post to the fan shroud; there is a handy hole (about 8mm) near where the coil mounts. While the ground stud on the wall near the battery seemed sound the body itself seemed to be the weak link in the grounding circuit. The transmission ground strap is a critical part of the ground system also; sometimes they need to be replaced just because. However, cleaning all major ground connections is very important. Remember that the alternator grounds to the fan shroud, and the starter grounds to the transmission case, so the engine and transmission need really good grounding to the chassis. A rusty chassis will not act as good as a ground as you might expect.
The parking lights should not drop the voltage significantly. That does indicate problems somewhere.