With apologies to MeatLoaf.
Sheila, I don't know your model and year of car, but there should be a dimmer control on the dash somewhere. Likely to be a rotary knob in the vicinity of the headlamp switch.
If that doesn't work, there is a fusebox where it is fairly easy to figure out which fuse is defective. Mine is under the hood, on the driver's side.
Even if there is no card or sticker to use as a guide, the german fuses are not like American cars, the fusible contact is on the outside, so it should be fairly easy to figure out which one does not have a continuous contact running from one end to the other. Make sure the lights are off and replace the "blown" fuse (hopefuly there are spares in the spare fuse rack in the fusebox, or in the glovebox). Then try the headlamps again, and see if that fixed the problem. If not, check the fuse again. If the same one is "blown" again, you have a "short" somewhere in that circuit.
If all else fails, go to your previous thread (question about starting), and at the bottom of each post, there is a link to email that particular member. Send your question to the member who helped you with that problem, he knows your car very well. Also, one of the members on the forum is named Patsy, and she is an expert on the 70's cars...
I hope this helps.