1968 brake lights dont go on

[JOHN MELVIN]

Ive run into a heck of a brake light glitch.

My brake lights do not come on.

1. The tailights work when the parking or front headlites are on, but the brakelights do not. With parking lights or front headlights off, brake lights will not come on when brake are applied. So it seems I have a problem somewhere in the breaklight switch circuit. Turn signals work fine wether headlites are on or not

I disconnected the brake light switch, and found it works fine thru a continuity check.

Now let me add this before the no brake light thing. 2 weeks ago, my drivers side outboard tailight would go dim if the headlites were on, and I applied the brakes. Just by chance, I was checking that brake tail/light housing this Saturday, and I accidentally grounded it against the rear bumper, a viola!, it worked fine, which makes the problem a poor ground. So I grounded it from the rear of the tailite housing to the frame, it worked fine. I didnt drive it anywhere afer this

So the next day, I walk out, and apply the brakes, and only the drivers side brakelights go on! Passenger side has tailites, but no brakelights!

Then magically, it progressed to no brake lights at all. Now I have just tailights if the headlites or parking lights are turned on. Turn signals work fine wether headlites are on or not. No brake lights at all

Man, my wiring under the dash that feeds the brake light switch circuit is so patched up with inproperly colored wires, there is no way I can trace where the problem lies

I beleive its a ground problem. But I have cleaned all ground straps, tailite housing grounds, etc, etc...........

One problem lies is that the wiring chart (Lectric Limited Laminated Poster)I have is very user unfriendly.

Could someone draw up a simplified (very simplified) wiring diagram (on power point maybe)that shows a simple brake/tailight circuit, that would show:

1. From power source to brakelight switch.

2. From brakelight switch to the 4 tailites/brake light housings, and to ground

(Remember, in my year (1968), back up lights are NOT in the tailight assemblies so I dont need the back up lamp circuit).

If you would please send to melvinjo@soc.mil

I may have to just compleley rewire to whole circuit. Cant afford a new wiring harness, and I cant trace the wiring because its so pacthed up

[Jim T.]

Re: 1968 brake lights dont go on

John you said that you disconnected the brake light switch and checked it and got a good check on the brake light switch disconnected. Did you check to see if you have electrical power to the switch?

[JOHN MELVIN]

Re: 1968 brake lights dont go on

Jim, Its weird.

Its WAS that periodically I got power at the brake light switch connector. Now, no voltage

[Chuck R.]

Re: 1968 brake lights dont go on

Hi John,

Just my very simplistic input.

Sounds like the lights are back feeding when the head light/emergency brake circuits are energized.

I don't think there is going to be any other way to solve your issue other than hands on tracing back from the brake light switch.

You may find that whoever owned the car before you had a cruise conrol or the like cut into your brake light circuit and removed it. Now the connection may be going south on you. Possible?

If the wiring is as chopped up as you say, I don't think a wiring diagram will help much in the dash area.

If you wish, I can photocopy the wiring diagram out of my 68 AIM for you. Let me know.

F.Y.I. Stop light wire color on driver's side appears to be yellow, Passenger's side appear to be dark green, all running lights appear to tie to a common brown.

According to the wiring diagram there could be as many as seven grounding points realted to rear lighting to include lisence plate and marker lights.

Chuck

[JOHN MELVIN]

Re: 1968 brake lights dont go on

Chuck. I agree. I beleive I will have to wire the whole brake light circuit myself, seperate from the wire harness. As I sadi, this harness is so chopped up, there is no way I can track the culprit down

I have a 68 aim diagram, as well as a large laminated lectric limited 68 wire diagram, but its very user unfriendly, at least to me

[Frank Savino]

Re: 1968 brake lights dont go on

I also had a problem with the brake lights on my '69. You may want to check to see if you have hazards/four-way lighs, the brake lights and hazards are on the same fuse. If you have no hazard lights you probably have a blown fuse. I would check your new ground wire for a possible short. Also this fuse is the bottom fuse in the block on the left. My fuse block had alot of corrosion, I had to clean it you to get a good contact. I hope the helps you some what.

Good luck

[JOHN MELVIN]

Re: 1968 brake lights dont go on

Thanks! I will definitley check all possible sources.

[Chuck R.]

Re: Hey What About

taking Frank's idea a step further, what about the main harnes plugs on the fire wall being corroded?

I seem to remember prior posts pointing to this as an on-going electrical corrosion issue.

Sooner or later right?

Let me know if no-one else what you find as my car came to me in milk crates and I just may run up against this one.

Chuck

[Jim T.]

Re: 1968 brake lights dont go on

John you could try this. At the fuse block about in the middle are two terminals you can connect a wire to that will give you 12 volts. Connect the wire from the fuse block to the stop light switch where the power would normally connect. You can make another jumper wire connection to run from the stop light output connection to the original terminal in the connector so the electrical power will be directed to the stop lights. I am assuming here that the connection on the stop light switch has two wires in a single plastic connector. If I was home I would look at my 68 and not assume there is only one plastic connector connecting to the brake light switch. Also I could be more descriptive of what terminal in the fuse block to connect the wire to to have continous 12 volts.

[JOHN MELVIN]

Re: 1968 brake lights dont go on

Jim,

Thats a great idea, I will do exactly that. Determining which post on the fuse block is hot is no prob. I beleive what you are decribing to me will bypass the steering column harness, therefore bypassing any chance of turn signal overide, correct?

My 68 brakelight switch does indeed, have a single, plastic connector, with 2 lines leading from the switch to the connector, and two lines leaving the connector

[John H.]

Re: 1968 brake lights dont go on

John -

Your brake light switch gets (battery) power through a 14-ga. orange wire from the fuse block, and when it closes, it feeds power through the white wire from the switch to the curved turn signal switch connector at the steering column. If the turn signal switch is working and in the straight-ahead position, it feeds power out to the brake lights from the two terminals adjacent to the white wire - yellow (left side) and dark green (right side). If you jumper power directly to the yellow and dark green terminals, that will bypass the turn signal switch and illuminate the brake lights; if that works and jumpering power to the white wire terminal on the curved connector doesn't, the problem is in the turn signal switch.

[JOHN MELVIN]

Re: 1968 brake lights dont go on

Man, what great posts. Definitley a head start, and easy to understand.

It does look like the wiring from the steering column is fairly intact, where it goes to the big curved connector