Mercury Sable GS

I have a 95' Mrecury Sable, whenever I turn the headlights on the clock
goes out. When the lights are out the clock works fine and keeps accurate
time. Any suggestions on where to start my search to fix the problem?

my boyfriend has an 89 mercury sable and he has big problem, trying to
change the water pump. and the screws broke off so now the pump is off but
too bottom screws are left in, how do he get them out, we've tried wd-40.
someone said try torch.