i got a 96 4d blazer 4wd with 160,000 miles. over the years the headlights have gotten dim. so i finally replaced the stock headlights. this didnt change anything. since then ive also replaced battery and alternator. seems like its getting worst now. hard to drive at night. any ideas yall have to fix this problem would be greatly appreciated. thanks

You could have a bad ground. I would check the ground wire connection for corrosion first. Trace the black wire from the headlights to where it connects to the metal of the truck. Disconnect it and sandpaper or wire brush both surfaces, then reassemble.

^^^^^^what he said

do you have a multimeter/voltmeter?