: dim tail light

02-06-11, 05:13 PM
erratic blinking. replaced 1 bulb. 2057. both lights are nice and bright on pass side. both driver side seem dim. changed 1 bulb and it is no different. has dual elements. the elements seem to alternate and glow dimly. is the alternating normal?

02-07-11, 10:27 AM
actually there is 1 light in trunklid and 2 lights in fender so 3 on each side of car. i suppose most folks do not take out bulb from housing and watch how it blinks. i had turn signal on and looked at bulb and the dual elements seem to alternate flashing. if i tap bulb, the alternating seemed to start and stop. i do not know if this alternating is normal. but anyway, all bulbs on the driver side seem dim. the pass side lights are much brighter. that is why i changed 1 bulb on driver side to see if it got any brighter. nope. maybe the wire harness connection has corrosion or maybe i have a poor ground somewhere.

02-07-11, 06:40 PM
This happened to me one time in my life. It was in a '79 Mercury Capri (like the Mustang). It ended up being the tail light ground. Easy fix but difficult to diagnose


02-07-11, 10:36 PM
i googled dim brake lights and got many hits. 1 thread said they had a bad bulb socket. put in new socket and fixed it. but the seville has 3 bulbs on each side. all lights work but all 3 are dim. i think pass side blinks slightly faster than driver side.