69 RT/SE no brake lights please help

[general rt/se]

Hello all, I have been trying to diagnose the no brake light issue on my General Lee for over a year and really need help with this.  A new turn signal switch did not solve the problem, and the brake lights did work at one time.  Since I built the car, the cluster lights, dome light, and flashers have NOT worked.  The turn signals, parking lights, headlights, etc all work.  I have power at the pink wire at the pedal, but when depressed, power disappears.  If I remove all taillight bulbs, the power remains when pedal is depressed, but it is gone as soon as one bulb is installed.  Any help would be greatly appreciated.

[rikubot]

I'm having similar problems. I'll post up if I get anywhere with mine. Good luck!

[BLK 68 R/T]

A lot of electrical problems can be attributed to grounding issues due to paint buildup, corrosion, etc. Try running an aux ground wire from the bulb socket to a known good clean ground and see if your light works. This can be done with a length of wire with alligator clips on each end. The same would be true for the other lights you mentioned, cluster frame must have good ground to the dash and the dash frame has to have a good ground to the body.

[cdr]

replace the fuse it my look good but can still be bad.

[general rt/se]

Thanks for the suggestions.  I did try the jumper wire for an extra ground from the body inside trunk to the bulb housing but that did not help.  I have tried a different fuse and also tested for continuity across the fuse.  I'm not very good with electrical work so its very frustrating.

[cdr]

make a long wire with alligator clips & go from + battery to the brake swith & see what happens

[BLK 68 R/T]

You could also unplug the rear light harness behind the driver side kick panel. Then use a test light or multimeter to check for power on the brake light wire. If you have power there when you press the pedal you can eliminate the problem being from that point back into the dash harness somewhere, and the problem is most likely in the rear portion of the harness. Might be a broken or wire going to ground in the rear harness.

[cdr]

he said the power drops out when the brakes are pushed

[BLK 68 R/T]

OP also says that if all the bulbs are removed the power remains. Just trying to work through a process of elimination.

[Back N Black]

Maybe the problem could be in one of the brake light sockets? instead of pulling all the bulbs, try pulling one at a time to pin point the problem. 

[general rt/se]

I will try a couple more things tonight, but yes the power is still there at the pedal with brake depressed, but goes away as soon as any one of the bulbs is installed in the harness regardless of which bulb.  I will unplug the harness at the kick panel to check for power when depressed but I am pretty sure it has power there until the bulb is installed.

[BLK 68 R/T]

My guess is the rear portion of your harness has an issue. When you have the plug disconnected behind the kick panel I would pull the harness out and do a good visual inspection on it looking for broken wires or bare spots. Also do a continuity test on each wire to make sure they are good.

[general rt/se]

Quick update, last night I checked for power at the kick panel plug, and two of the wires have power with pedal depressed and bulbs removed which is the green and I think black wire (two wires on same end of plug have power).  I then unplugged it and ran a jumper connecting only the black terminals, and when a bulb is installed the power remains.  However when I do this to the green wire the power goes away.  I then removed the green wires from the plug ends, plugged it back in, and ran a new wire from the green terminal of dash harness to the harness in the trunk.  No difference.  I thought this isolated the problem to the green wire but I'm not sure because it could be feeding back into something else and losing power.

[Pete in NH]

Hi,

Welcome to the group.

You can chase these kinds of problems forever if you don't have a good wiring diagram as found in the factory service manual. Also, a cheap little multi meter/ohm meter from Radio Shark or Harbor Freight. Some thing is wrong in the rear wiring harness but, with out a diagram as a guide you have no real idea how it is supposed to be. You can also find a wiring diagram at Mymopar.com.

So, my first question is do you have a diagram and meter?

[general rt/se]

Hello and thanks for the welcome.  I do have a complete '69 service manual and multimeter but like I said I am not an expert with electrical work.  I have some experience, but have not been able to solve this one.  It seems that there is power in the correct places, its just that once the bulb(s) are installed it reroutes and disappears somehow.

[Pete in NH]

Okay, if you look at the diagram you will see a big splice in the trunk wiring where all the grounds (black wires) come together. use your meter in the lowest ohms letting and make sure that point is really grounded well to the metal of the body. If that ground point is not well connected to the body it can cause the issue you describe when the bulbs are in the circuit.

Let me know if you need help setting up your meter.

[general rt/se]

I know exactly where you are talking about where the ground wires join together.  I will add a ground to the body directly from that point and see if anything happens.

[cdr]

the grounds in the rear have nothing to do with power dropping out at the brake switch , read what i said earlier.     Insert Quote
make a long wire with alligator clips & go from + battery to the brake switch & see what happens

[general rt/se]

Dad came over yesterday to help troubleshoot and just basically listen to my frustration with the lights.  I decided to try all new bulbs including a pair of 1003's on the inboard sockets.  No change, and now no running lights either.  Then I tried isolating the left from the right and vice versa.  During this process it blew two fuses in the running lights location.  Then after resplicing the wires, and installing new fuses in both locations, the lights work!  Therefore, I am not sure what the real problem was, or if they will continue to work.

[general rt/se]

The electrical gremlins have come back to visit, and the brake lights are no longer working.  Now I am getting ready for Carlisle, and need them fixed.  I have tested for power at the fuses, and they are okay.  There is power at the pink wire at the pedal, but goes away when pedal is depressed or when jumping the two terminals at the pedal.  The taillights work, as well as the turn signals.  I tried adding extra grounds to the tail harness.  Any advice is appreciated with this frustrating problem.

[cdr]

are the fuse panel connections corroded? pull the fuses out that you replaced last time & clean the fuse connections.

[BrianShaughnessy]

I have had multiple problems getting Sinnamon going with the tailights...   I'm still screwed for the time being but my problems are with the turn signal switch.

I had the column apart so I put in a $60 repro switch.
Upon testing in car,  I had turn signals but no brake lights.

Respliced in the old original turn signal switch.
Now I have brake lights and no turn signals.

E-booger recommended a Daniel Stern turn signal switch ( $105.90 shipped ).   It's on the way.  Made by original MFG from back in the day.   http://www.danielsternlighting.com/

[Highbanked Hauler]

My guess is the rear portion of your harness has an issue. When you have the plug disconnected behind the kick panel I would pull the harness out and do a good visual inspection on it looking for broken wires or bare spots. Also do a continuity test on each wire to make sure they are good.

Blowing fuses means you have a dead short somewhere. It kinda sounds like a bare wire contacting intermittently. Also having some power then it goes out sounds like feed back which comes back to a ground.. I have had that problem with signal lights a few times.