‘69 Dart Tail Light Issue. Yes, another one of these…

[OregonSwinger]

Hi, first time poster, but a long time visitor. Can’t tell you why I took me so long to get here, but I’m here!

I’ve chased around this website for about a year looking for answers on a tail light issue.

‘69 Dodge Dart 340 / 4 speed. The owner before me botched, and I mean botched the wiring. I spent the last two weeks removing the engine front harness and tail light harness.

I started with the rear half of the car trying to fix a tail light issue.. turn signals worked, brake lights worked (sometimes) and same with the tail lights. I changed out the back harness and put some LED bulbs in, voila! They worked! HOLY glory! Then I took on the engine forward which was an absolute nightmare, including two 5 post relays, a bunch of miscellaneous working, etc, etc.. finally got it all back together and very tidy / easy to work on in the future.. no tail lights again. Brake lights work, turn signals work, hazards work.. turn signal switch was replaced maybe, 5 months ago.. (add 10 driving miles to that)… flasher relay replaced, went back to regular bulbs.. I’ve checked all the fuses, replaced all the fuses.. at thus point I’m burning out. Any suggestions? I’ve read as many articles and forums I can on this subject and just keep chasing dead ends and replacing parts..

Any suggestions, recommendations, insight, words of encouragement at this point would be greatly appreciated.

I’m also in Oregon, shout out to anyone local!

 

[Mike69cuda]

I chased electrical gremlins for a long time on mine. If I had it to do over again I would buy all new M&H harnesses from year one and change it all out.

Do the taillights work if you swap the LED bulbs back in? Looking for clues…..modified wiring is hard to troubleshoot.

 

[4mulas]

Running lights are on a different circuit than stop and signal. It sounds like to me that previous owner may have taken a signal off the front running lights to tie into the rear running lights, then since you corrected all the botchery they don’t work again. I say this as you said the under hood was a mess with 5 relays etc….

Have you ever checked or replaced the headlight switch itself?

This will be easier than you thought to find and you WILL get it! I am assuming you have a proper wiring diagram for the year/model you are working on? If not, get one. Then it is simply a matter of tracing back and following every wire to make sure it’s correct. It will probably be something simple…

 

[OregonSwinger]

I chased electrical gremlins for a long time on mine. If I had it to do over again I would buy all new M&H harnesses from year one and change it all out.

Do the taillights work if you swap the LED bulbs back in? Looking for clues…..modified wiring is hard to troubleshoot.

Hey Mike, I haven’t tried putting the LED lights back in since they didn’t work originally. The only wiring that wasn’t replace back to factory.. or reproduction factory was under the dash. I’ll put them back in and see if anything happens again..

 

[OregonSwinger]

Running lights are on a different circuit than stop and signal. It sounds like to me that previous owner may have taken a signal off the front running lights to tie into the rear running lights, then since you corrected all the botchery they don’t work again. I say this as you said the under hood was a mess with 5 relays etc….

Have you ever checked or replaced the headlight switch itself?

This will be easier than you thought to find and you WILL get it! I am assuming you have a proper wiring diagram for the year/model you are working on? If not, get one. Then it is simply a matter of tracing back and following every wire to make sure it’s correct. It will probably be something simple…

I haven’t! That’s probably the most logical next step for sure. I have the back seat out right now, but I’m also tempted to pull the front out. It sure is tight working inside the dash at 6’1 / 200.

I do have a large factory mechanical manual with every diagram on it. I should start trying to chase wires inside the dash too..

 

[4fortyDemon]

Had a 68 Cuda come in the shop a few weeks ago. No taillights working. Short story, headlight switch was faulty. Just a thought.

 

[dano]

Nice car BTW.

Its easier to pull the dash out to check the wiring behind it. Have you check the harness from the drivers side kick panel all the way to the back tail lights? Like pulled seats, door plates, kick panel and just inspected it?

 

[OregonSwinger]

Had a 68 Cuda come in the shop a few weeks ago. No taillights working. Short story, headlight switch was faulty. Just a thought.

Replaced it this afternoon. No dice! However the female plug looks like it maybe got hot / melted at one point. Gonna try to source one.

If anyone can direct me towards a reliable repro pigtail, I’d greatly appreciate it!

 

[OregonSwinger]

Nice car BTW.

Its easier to pull the dash out to check the wiring behind it. Have you check the harness from the drivers side kick panel all the way to the back tail lights? Like pulled seats, door plates, kick panel and just inspected it?

Thanks dano! I replaced the the engine front and the taillight harness already. It looked fine. I’m not sure what it takes to
Pull the entire dash out, but not looking forward to it…

 

[OregonSwinger]

Update: problem fixed. Back of the fuse block. Battery feed - Q3-14R* (14 gauge red w/chaser). Cleaned the damn contact, blew it out with some “dust off” and it works again.

I appreciate everyone getting me motivated enough to dig a little deeper on it. Cheers to you all.

 

[Mike69cuda]

Hey Mike, I haven’t tried putting the LED lights back in since they didn’t work originally. The only wiring that wasn’t replace back to factory.. or reproduction factory was under the dash. I’ll put them back in and see if anything happens again..

Ok, I thought I read that the LEDs worked at some point…..nevermind….

 

[Mike69cuda]

There is a connector back by the gas filter tube on the trunk floor. The rear window seal leaked on it on my car and corroded the connector.