I just purchased a used 1991 740 turbo wagon.... I can say I am in love with this car. I am having trouble with the brake lights. I started out with only having the passenger brake light not working, the bulb indicator light was coming on when I applied the brakes. I went to the local auto store, picked up some replacement bulbs ( they gave me 25w/6w the manual calls for 21w/5w) They said that the wattage would not make a difference. So I replaced the passenger side ( Tight spot for large hands) I didn't bother to test got in the car and the indicator light stayed off when I applied the brakes so I figured all was well. It turns out it wasn't and now both brake lights are not working, the third brake light in the rear window still works. also the passenger turn signal in the rear no longer works. Any ideas where to start? What seemed like a simple fix has now escalated. I appreciate your patience and any help you can offer. Sorry for the long post

 

the chrome base european style tail lights work much better than the brass base american ones. I've been able to find these chrome base lamps in the auto parts stores on Sylvania hang cards that are green and say OEM

its hard to say how replacing the right side brake light would affect the left side brake light... it shouldn't do that.

 

Does the difference in wattage make a difference?

 

the difference in wattage might set off the bulb out sensor, but they'd still light up.

 

Thanks for the help, I think I have it sorted out. I really think the housings themselves have corroded and need to be removed for a through cleaning. Also I noticed one of the sockets won't let the bulb fully seat. I have managed to wedge it with a small block of wood till I replace the tail light assembly. Funny thing when I first installed it worked without the ignition on. When I started the vehicle the tail light lit when brake was depressed light when out. I had my wife start the car press the brake as I slightly rotated the bulb socket till the brake light came on, then replaced the wood wedge. A good temporary fix till a new one can be purchased. This is a great site for information, I am glad to have found it. Cheers!