No Brake Lights, Help!

[lonetreesteve]

My brakes lights on my '72 240z/4-speed don't work properly. For some strange reason when I turn on the lights, both the brake lights and the tail lights come on. I've read through the archived threads and have checked out all of the following so far:

All of the connections on the rear tail light are correct.

All of the fuses are good and are the correct ones in the appropriates places.

All of the bulbs are correct and they all work.

I changed out the brake switch on the pedal apparatus.

I checked out all of the connections.

I changed out the headlight switch.

Certainly someone has run into this problem before.

Thanks!

[JimmyZ]

Very strange. You havent done any switching of the wires on the steering column?? That would be my first thought. The bulbs are 1157's for arent they??? For fun try the hazards and turn signal light to see if they are wired right.

[Arne]

Sounds like a possible bad ground at the back of the car, to me.

[lonetreesteve]

Very strange. You havent done any switching of the wires on the steering column?? That would be my first thought. The bulbs are 1157's for arent they??? For fun try the hazards and turn signal light to see if they are wired right.

Jimmy, I checked the brake light bulbs and they are both 1157s. Hazards and turn signals all work fine. I'm pretty sure that all the wires are connected correctly under the steering column. I'll check again.

I'll also check the grounds in the rear as Arne suggested.

Thanks guys

[EScanlon]

Hazards AND T/S both work "fine" yet the Brake lights are on with the Tail? Since the Haz and the T/S both use the same filament as the Brakes, it might behove you to double check the wiring to the Stop Switch.

Something changed recently... you weren't having this problem before. Try to remember what you last did to see if it might have had an impact here.

You might check that you don't have a "cross-threaded" bulb in one of those sockets while you're checking the grounds.

E

[lonetreesteve]

I checked out the wires in the steering column and in the rear again and everything looked correct. I have attached pics of the steering column, the switch on the upper part of the driver's kick panel and the rear tail lights. Do you see anything that might be connected incorrectly?

[JimmyZ]

I agree with E. You changed something alright.

I noticed that you changed the light switch. Although you can't screw up on the big plug it's possible to screw up and misplug the individual wires on the steering column. Try unplugging some of those individual wires one at a time and observe whether your brake lights out. (Go out with the lights on that is) I've managed to plug the wrong ones in the past.

This is probably your problem. It may also be that you have a switch from a year of Z which doesn't jive with your earlier model.

I'm sure you've tried disconnecting the brake light switch already. (Just to see if the switch is misadjusted) If it were misadjusted the brake lights would stay on of course.

IF I'm reading this right then all six of your rear 1157 bulbs are coming on when the light switch is turned to "on".????? This isn't a simple matter of someone swapping your bulbs in their sockets to have fun with you.

Let us know what it is. Now that I took a little more time to read your post I'm betting on the wiring in the column or an incompatible switch.

Jim

Edited November 9, 2008 by JimmyZ

[Arne]

I still suspect a ground issue. The bulb sockets on a 240Z require a good ground in the rear wiring harness. When you turn on the tail lights, the power goes into the dim filament and to the brass base of the bulb for ground. If there isn't a good ground at the black wire, the power then feeds backwards through the bright filament and back up the wiring until it finds a way out.

This seems more likely to me than the possibility that the tail circuit is crossed with both brake circuits.

Here's a couple of simple tests. Turn on the tail lights (which should light the brake filaments as well). Leave the ignition off. What happens when you use the turn signal (either side)? Normally, the brake lights for what ever side turn signal you activate should go out. If that doesn't happen, I don't think the wiring is cross-connected.

Also. try adding a separate ground wire jumpered into one of the black wires at the tail light connection. See if that has any effect.

[geezer]

What happens when you step on the brakes with the headlight switch off? I'm guessing only your brake lights will come on and the turn signals will still operate fine. Does the problem only occur when the headlight switch is turned on? I'm inclined to follow E's thought about a socket problem first and bad grounds as an unlikely second.

[Zs-ondabrain]

Ok, Here's my take on it. Take it for what it's worth..

I looked at the pictures and the headlight switch wiring looks to be correct, as is the T/S switch.

The third picture is your horn relay so don't worry about that.

I would suggest this....

Remove all of the rear taillight bulbs

Make sure all of the single wire sockets have only 1156 bulbs.

Make sure there is minimal or No corrosion (use dielectric grease on each and every bulb in the Z.

Make sure only 1157 bulbs are in the 2 wire sockets. If only one of those 1157's are twisted wrong or forced in incorrectly, there will be issues, Like brakes coming on with the parking lights.

The parking lights have nothing to do with the brake lights, so to speak. The combo switch controls the parking lights. The brake switch (on the pedal) and the T/S switch, control the brake lights. The turn signal switch controls the brake lights as well as the turn signals and the both go to the Hazard switch.

I would start with the bulbs in the back then check the hazard switch. ALSO!! Check the 2 center wires on the 6-wire metal switch on the T/S switch. They are green and green/yellow. Solid green is the wire from the flasher and the green/yellow is from the brake switch, if the solder has flowed and they are touching, you may get a constant brake light. But that would'nt explaint the ON with the Parking lights.

Dave.

P.S.

If all else fails, Check each wire on the taillight harness's on each taillight. There may be a crossed wire inside the vinyl tubing, I've seen it happen and it will cause the problem you're having.

[JimmyZ]

God we should really try to have some betting allowed on the site. I'm sitting here thinking about it while comparing pics. It does look like everything is good on the column as Dave said. (Just looked at mine)

Ok Ok Ok

Check the wires down at the brake light switch. The two green wires with the yellow stripes plug into the brake light switch. It might be possible that some other wires were mistakenly plugged in. The brake light switch has two GY wires on it.

[lonetreesteve]

Well guys, after I got back from the movies and dinner with my wife and 2 of my kids, I made some progress thanks to your good advise. I changed out both wiring harnesses, cleaned all the sockets and checked all the bulbs again (all the bulbs are new as they were before). The good news is that the brakes don't come on with the lights when I turn the lights on, but there are still no brake lights with or without the lights on.

I did trade out the light switch earlier, but the brakes didn't work before I traded it out. I switched the green/yellow wires around on the brake switch, but no luck. I will try putting the original brake switch back in tomorrow (it's 10:20 pm here in Colorado) Thanks, guys I think we are getting closer.