Since I bought my civic 1997, a year ago, the driver side headlight has been shining weak. I changed the bulb once, it still shows weak. I took it to the electrician, he turned a nut tight and it worked for a couple of months, but now it's shining weak again. Could anyone tell me why this is?
A poor ground will give you the symptoms you are seeing. A wiring diagram will show you that there is a ground but not where it is located. The diagram I found shows a frame ground that is a black wire. I would start by looking for the black wire on the offending headlight and follow it away from the light as far as you can. If you are lucky at some point you will see a black wire that is screwed or bolted to the frame or body of the car. Remove the screw clean the area around the hole with some coarse sandpaper or a stiff wire brush until you see bare metal. Reinstall the screw if you are unable to get the screw tight due to hole being to large get a larger sheet metal so you can get it tight.