I feel so stupid. This is such a seemingly small problem but I can't seem to resolve it. My 1985 944's headlights work on low beam. However when I try to put them on high beam they just turn off completely. I have changed the bulbs already. because they were getting dim anyway but the same thing is happening with the new ones. Then I wondered if my high beams and low beams were on different fuses and the high beam one might be blown. But it appears that they are on the same fuse so it is not that either. Do you guys think it could be the dimmer switch?
Check the wiring. Make sure a wire didn't come loose or burn out.
Let's look at the whole system:
1) Switch in the cabin
You've ruled out 3 and 5, so it's either the switch, a relay, or some wiring somewhere between.
Best place to check for dodgy wiring is at the connections at either end (switch, relay, fuse)
Do you have a multi-meter?
No I don't have a multi-meter, sorry.