Just recently purchased 1996 BMW 328i sedan 175K Odemeter reads, Tail lights won't illuminate, interior dash lights won't turn on at night, so can't see speedometer, or gear changer in the dark, Also car was scanned for inspection both o2 sensors need replacing, very rough idling, then sometimes car stalls out. When reaching about 50 mph vibration starts from back of the car as if I had a system in the trunk. I'm stumped any suggestions?
Rear End Diagnostics:
1.) Get the car on the lift and check the subframe bushings, control arms (look for bends or cracks), anti-sway bar end links being broken.
2.) Check and make sure the axles are bolted down properly and no missing bolts. Some low-end Miguel, Juan, and Jose shops usually do quick work but not good work and things like this happen ALL the time.
3.) Check for bends, warps, and cracks in wheels. Also make sure the weights are still on the wheels.
4.) Lift the trunk carpet and do a thorough inspect. Look for crinkles in the metal or poorly banged out metal work. This is highly suggestive for a severe accident.
Tail Lights Won't Illuminate:
1.) Open the trunk and look on the left lower corner of the trunk and you will see a cover and wire coming out.
2.) Grab a razor and cut the cover and inspect the wires. You will notice some cracks and breaks in the wire. Replace all as necessary. If that doesn't work...
3.) Check the connector going to the tail lights. Make sure there is no oxidation between the connector and the wire. If there is any, grab a soft wire wheels and clean it up. Apply soem dielectric grease and reconnect.
4.) Check your brake light switch. If it hasn't been replaced and your "Check" light is on and your OBC reports "Brake Light Failure", replace this unit. However, with the car I am finishing up, I noticed that the brake light switch was bad, but wasn't showing the "Check" light or "Brake light failure" warning. It was doing the same things you are describing.
5.) Check and make sure the Lightbulbs are the right type, and the bulb connectors are making clean connections to the metal plate frame.
6.) Check and make sure the alignment is as even or within factory specs, and make sure the rear shock mounts and bolts are not kyboshed.
Speedo is dark:
1.) Remove the speedo and just do yourself a favor and replace all the bulbs you see on there. They're dirt cheap.
2.) Depending on the year of your E36 (yours being a 96), look on the right side of your steering wheel, under the speedo. You will see a rotating dial and a symbol above it. Rotate the dial upwards for brighter illumination, down for something more dull or darker illumination. If that doesn't work, that dial is also another culprit (provided your electricals are all in working order and you have no other shorts). They're cheap from the salvage yard.
3.) If the salvage yard piece doesn't work, get a new unit. They are about $60 - $80.
4.) If that doesn't work, then you most definitely have a fuse out. Replace the fuse.
5.) If replacing the fuse doesn't work, then you have a short or bad speedo.
O2 Sensors:
1.) *Facepalm* Just replace them...