The Stovebolt Site Forums The Shop Area The Electrical Bay Brake Light question

I noticed yesterday that my passenger side brake light is only about 1/2 as bright as my driver side. I replaced the 1157 and no change.(only one filament is lighting) I checked the connections and the housing and noticed that the ceramic material that surrounds the wires as they enter the back of the housing is all cracked. Im not sure what the culprit is here. I have a 57 3100 and the wiring is original-stiff and pretty nasty. I am usless when it comes to electrity so I am stumped. So do I need a new tail light assembly? :confused:
Thank you.

Kevs57,

When you look at the lamp, make sure it is the brake filament that is illuminating. This should be the larger of the two. The assembly has to have a good ground to the bed and frame. Make sure the attachment is clean and tight. If the lamp is working, but dim, it might be telling you it can't find a clean path back to ground.

If it is a ground problem with the light assembly, when the taillights are on you might see a dim taillight too.

Does your truck have turn signals? What does the light do on a right turn? If you have any doubt about the lampholder, it might be best to replace it now and see if that cures the problem.

Stuart

What does your pass. side tail light look like (test by switching the parking lights on) is it brighter than the driver's side? If so, the wiring is reversed on the pass. side, just switch the wires.

Thanks guys. I dont have turn signals although the plan is to eventually add them. I didnt think to check the park light aspect of this so I will do that after work. I think the smaller filament is lit not the other one. I really need to take a course on this so that I can at least get these fundamentals down!

Kevs57,

If you don't have turn signals, it pretty straightforward. Two wires to each light assembly. One wire for taillights...small filament, and one wire for larger, brighter filament which is brake light. These wires probably go to one light and are spliced there to go across the bed to the other light.

The 1 minute auto electric course tells you the power comes out of the battery, through the wire to the light. It goes through the light and does 'work'...makes the filament glow, then it must have a path back to the battery. This 'back to the battery' path is the entire frame and structure of the truck. You can see that this 'huge wire' is important. Everything must be bolted and connected to allow the power to reach the negative side of the battery.

Stuart

Thanks Stuart. So if I step on the brake pedal (no head lights or park lights are on)and a filament lights up but is very dim...do I assume that electricity is getting there but a connection is not complete?

You got it Kev. It is grounding through the tail light. You need to trace your ground. With a jumper wire start at the socket base With one end of the wire on the frame. If that lights it up go to the light housing. If that lights it go to the bracket. You will find it.

Kevs57,

Wrenchbender's procedure is the ticket. It must be the large filament that is trying to light with the brakes. The only other snafu would be a damaged wire or connection from the drivers side light to the passenger side light. If the wire is just hanging on by a thread, it won't pass enough current to light the lamp.

A simple 'wiggle-tug-jerk' test usually turns up marginal wiring.

Stuart

OK. Last night I turned the headlights on and when my daughter stepped on the brake pedal the passenger side light goes out-everything, no light at all.Wrenchbender, when you say socket base do you mean touch the wire to where the bulb is attached?

Exactly! Sometimes the base has lost its ground to the light housing. That is the starting point.