Grounding Issue?

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carfreak6970

carfreak6970

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I was driving home from work last night sitting at a light with my left turn signal on (my 68 Dart Convertible). The biker behind me informed me my brake light was out. I am assuming it was only my right one. But I thanked him and moved on. Once I got through the light and across the bridge I hit another light. And again, the biker informed me that I have no brake lights on either side. A little concerning, so when I got into the garage I verified that my brake lights do not work. However, the turn signals illuminated the tail lights. When the headlight switch is pulled out the tail lights come on and at that point the brake lights & turn signals work as they should. So I am a little confused.

The car has LED tail light bulbs that were spec'ed out by SlantsixDan. I have the turn signal flasher that he spec'ed out for LED tail lights. And the car has cruise control (so it has a different than normal brake light switch). The only thing that changed between the last time I drove the car and last night was I used the cruise control just to see if it worked (it did).

Am I correct in my thinking that the issue I am having would be a grounding issue? I did try taking a jumping wire from a tail light housing stud to the trunk light switch (figured that was my best ground) but it did not change anything. I guess my grounding issue could be from the socket to the tail light housing. Am I on the right track here?

Thanks
 
It is either a grounding issue, or an LED driver issue if you have a driver.
 
Demonracer said:
It is either a grounding issue, or an LED driver issue if you have a driver.
Click to expand...
No. That is, not necessarily. I did not read that the OP had checked for switched brake light power going INTO the turn signal switch. Could be a problem in the brake like switch circuit, or the switch. IT COULD ALSO be a problem in the TS switch itself.

You cannot make assumptions. You have to get DIRTY. You have to ROLL UP YOUR SLEEVES, and you have to get out the wiring diagram, a meter, clip leads, test light, maybe some spare bulbs and GO TO WORK

Start by finding the brake light switch wire, normally white, that enters the turn signal switch connector. That circuit is operational at all times, no key needed. Probe the connector and depress the brake. Should have power with brake pedal depressed. If not crawl under and access the switch. One side of the switch should always be hot. If not find out why. If the output of the switch is not working, either the braket/ switch is loose/ out of adjustment or a bad switch

If you DO have power out of the brake light witch (entering the column TS switch, now look up the wiring code for the rear signal lamps and probe them. With the switch centered, you should have brake power there when the pedal is depressed.

If you DO have power there, it's a LED / grounding issue. If you do not, then you have a TS switch issue.
 
For a simple and cheap test you could replace the LEDs with standard bulbs and see if you can duplicate the issue
 
67Dart273 said:
No. That is, not necessarily. I did not read that the OP had checked for switched brake light power going INTO the turn signal switch. Could be a problem in the brake like switch circuit, or the switch. IT COULD ALSO be a problem in the TS switch itself.

You cannot make assumptions. You have to get DIRTY. You have to ROLL UP YOUR SLEEVES, and you have to get out the wiring diagram, a meter, clip leads, test light, maybe some spare bulbs and GO TO WORK

Start by finding the brake light switch wire, normally white, that enters the turn signal switch connector. That circuit is operational at all times, no key needed. Probe the connector and depress the brake. Should have power with brake pedal depressed. If not crawl under and access the switch. One side of the switch should always be hot. If not find out why. If the output of the switch is not working, either the braket/ switch is loose/ out of adjustment or a bad switch

If you DO have power out of the brake light witch (entering the column TS switch, now look up the wiring code for the rear signal lamps and probe them. With the switch centered, you should have brake power there when the pedal is depressed.

If you DO have power there, it's a LED / grounding issue. If you do not, then you have a TS switch issue.
Click to expand...
Thanks for that. I guess that is the best way to go about it. I will try to give that a go around, thanks!
 
carfreak6970 said:
Thanks for that. I guess that is the best way to go about it. I will try to give that a go around, thanks!
Click to expand...
Do you have diagrams? You can download the factory service manuals and aftermarket 3rd party diagrams, not always accurate to options but sometimes easier to follow, for free, at MyMopar.com
 
Did the retro fit ever work?
 
So, with the headlights on, you have no problem, but, with the headlights off, you do? Doesn't sound like a brake or turn signal switch problem. Sounds more like grounding or crosswiring there somewhere. The taillight/headlight circuits should be totally separated from the brake/turn signal circuits. Most of our Mopars have the brake light and turn signals using the same filament (the big one) in the 1157/1034 bulbs, both front and rear. The other filament in the bulb is for the park/taillights. A bad ground, wrong bulb, or corrosion in the socket can cause all sorts of strange results.
 
67Dart273 said:
Do you have diagrams? You can download the factory service manuals and aftermarket 3rd party diagrams, not always accurate to options but sometimes easier to follow, for free, at MyMopar.com
Click to expand...
for what ever reason MyMopar does not have the 68 manual. Unless they got one in the past couple years. But I have the 68 Dodge FSM printed out in a binder
 
carfreak6970 said:
I was driving home from work last night sitting at a light with my left turn signal on (my 68 Dart Convertible). The biker behind me informed me my brake light was out. I am assuming it was only my right one. But I thanked him and moved on. Once I got through the light and across the bridge I hit another light. And again, the biker informed me that I have no brake lights on either side. A little concerning, so when I got into the garage I verified that my brake lights do not work. However, the turn signals illuminated the tail lights. When the headlight switch is pulled out the tail lights come on and at that point the brake lights & turn signals work as they should. So I am a little confused.

The car has LED tail light bulbs that were spec'ed out by SlantsixDan. I have the turn signal flasher that he spec'ed out for LED tail lights. And the car has cruise control (so it has a different than normal brake light switch). The only thing that changed between the last time I drove the car and last night was I used the cruise control just to see if it worked (it did).

Am I correct in my thinking that the issue I am having would be a grounding issue? I did try taking a jumping wire from a tail light housing stud to the trunk light switch (figured that was my best ground) but it did not change anything. I guess my grounding issue could be from the socket to the tail light housing. Am I on the right track here?

Thanks
Click to expand...
LED's can be a funny thing. I had wierd issues when I replaced all the bulbs in my Duster with LED's (except headlights). Had no turn signals when the headlights were on but when off worked fine. I was using the special LED turn signal relays that had a ground wire pigtail. After much work and pulling hair out I replaced the brake light bulbs with standard OE bulbs and everything worked. I was so tired of messing with them I called it a night and never looked back.
 
Ricks70Duster340 said:
LED's can be a funny thing. I had wierd issues when I replaced all the bulbs in my Duster with LED's (except headlights). Had no turn signals when the headlights were on but when off worked fine. I was using the special LED turn signal relays that had a ground wire pigtail. After much work and pulling hair out I replaced the brake light bulbs with standard OE bulbs and everything worked. I was so tired of messing with them I called it a night and never looked back.
Click to expand...

I have never been able to make working my Demon with LEDs. Even with so-called "no error" LEDs, or with "Electronic for LED" flashing units. There was always something misfunctioning.
As soon as I came back to bulbs, everything returned to normal :)
LEDs? No, thanks.
 
If the turn signals and park lights are working, then it isn’t a ground.
 
It could be if the headlights are acting like one when they're on. I've run across weirder things.
 
After reading the last paragraph a coupla times, I think you are really close, but contacted 2 maybe wrong things.
Try vise- gripping one end of jumper to the trunk lock striker, the other end to the actual bulb base, after you pull the socket outta the housing.
If it works as it should, repair the grounds to tailite housing and bulb socket, and to the bulb, and that black? wire sticking out of the harness, that screws into the sill inside the trunk apron, that you lean over, just below your nuts .
Good luck ,
 
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Ricks70Duster340 said:
LED's can be a funny thing. I had wierd issues when I replaced all the bulbs in my Duster with LED's (except headlights). Had no turn signals when the headlights were on but when off worked fine. I was using the special LED turn signal relays that had a ground wire pigtail. After much work and pulling hair out I replaced the brake light bulbs with standard OE bulbs and everything worked. I was so tired of messing with them I called it a night and never looked back.
Click to expand...
Same here. On an old car and even a 2008 Honda tried to use some conversion bulbs no dice. Put new glass USA bulbs in was just fine.
Yea i am an old guy consider a,2008 new car.
 
M
340six said:
Same here. On an old car and even a 2008 Honda tried to use some conversion bulbs no dice. Put new glass USA bulbs in was just fine.
Yea i am an old guy consider a,2008 new car.
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Me too. I have 10 vehicles and 2008 is newer than any of them!
 
Well the thing I’d also like to add, is these bulbs have been in the car for over 4 years now with no issue. So this not working thing is fairly new
 
carfreak6970 said:
Well the thing I’d also like to add, is these bulbs have been in the car for over 4 years now with no issue. So this not working thing is fairly new
Click to expand...
That statement means nothing. Don't allow yourself to be led down the wrong path by that kind of thinking. Something is wrong, because something has gone wrong. What have you tested to try and eliminate parts? AKA power to to and from the brake switch, have you checked the rear lamps for grounding, or maybe tried old style bulbs "just to see" or what?
 
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