when i turn the switch for the headlights to come on the dont come on and my dash dosent light up either. the running lights work when i have the switch in the middle but when i put on the headlights absolutly nothing comes on i checked the fuses and its not that what should i do? its a 91 740 sedan

 

Do your hi-beams work? 1. make sure your bulbs are good. 2. if so most likely a bad relay. I haven't worked on many 740's but I believe the relays for the 740's are behind the ashtray. Remove the entire ashtray and you should see them. On the back of the ashtray there should be a list that tells you what each relay is for. I believe the headlight relay is silver but not 100% sure. I know it's not the tall white relay(overdrive relay) nor the stubbier short white realy(fuel pump relay). you will also need to unscrew the lighter to get to them. fairly easy to do...If you have a test light you can test for power when you have the switch in the "on" position. If no power it's either the relay or the switch itself. Start with the relay..Good luck!!!

 

i tried the relay and its not that i know it was the correct one becuase i went on to this web site http://www.davebarton.com/pdf/relay_87_700.pdf i tried two different ones and nothing happend its not a fuse either also when i switch it from the parking lights to the headlights the whole dash goes out. i honestly dont know what to try next.

 

the high beams do work though

 

sounds like a bad switch itself or a bad dimmer switch...rheostat. Go get a used switch and rheostat at a junk yard...one of them should solve your problem...