Thanks for the pointers. It ended up being the rear passenger socket. After I swapped it out everything is functioning as it should be with all of the external bulbs swapped over to LED’s. My best guess is the taillight circuit must have been back feeding through the direction/stop circuit back to the cluster hence functioning properly without the park/running lights on and the weird direction telltale behavior in the cluster. Again, great write up on this subject and chalk up another black ‘79 converted to LED’s.

 

Great to hear you found and fixed the problem! And are successful converting your external lights with more visible LEDs. Funny, both Bikespace (who made the excellent write-up on his '80 conversion) and myself had issues with a rear Turn/Brake light socket. On mine, the left outboard socket, had a plug-in spade partially broken off. I was able to build some "thickness" of the spade with solder, plugged it back in resulting in a solid connection, and all worked. Though, when the temperatures cool off a bit here, I plan to replace the socket with new.

Enjoy driving that black '79!

 

Yup! Mine failed internally. I think it's the same socket 75-82. You can see in this photo of my 80 that the tip of the crimp connector had broken off. So, same root cause, and same symptoms, for anyone reading this in the future. I replaced all four sockets.

LED-swapped Black 79s are the best looking Corvettes!

 

Thanks! Worked great for my '78 LED upgrade.

 

Awesome to hear, PBI.

 

I put the White/Amber LED Switchbacks on the front, LED's in all of the Side Marker Lights, Red LED's in the rear Tail Light/Turn Signal/ Brake Lights, White LED's in the Back-up Lights. The only thing I had to do was change the flasher in the fuse block to the LED Flasher with a ground, and I added a Accessory Hot wire running to the hot wire for the front parking lights with a Dioad behind it so the rear lights are not feed off of it. Now when the key is turned on the front lights come on white like a Daytime Running Light should but the only other lights to come on are the front side marker lights (I'm not sure if I could have tapped into it further down the line to keep the side markers off but I'm okay with it) and the turn signals still flash normal and Amber. I just wanted White DRL's that come on automaticly when the car starts and make it more visable coming down the road.
I did also change our all of the front and rear sockets, that darn ground wire broke on the rear ones like Bikespace was showing so I just did them all.

All bought from Amazon:
Auxbeam XD000182-US 1157 Switchback LED Bulbs
Auxbeam FG5E677F 1157 Red Superbright LED Bulbs
United Pacific 90652 LED Flasher with the Polairty Reversing Base
RVZONE RVZONEBAY15S 1156 White LED Bulbs (for back-up)




Heat shrink butt splices

Red LED

Ran the ground to the bolt by the steering column

 

PBI,
I just purchased a ’78 that the previous owner did the LED upgrade. All the external light bulbs are replaced with LED’s except for the headlights. The 4 side marker lights don’t light up and the hazard lights don’t work. New electronic flashers are installed. It looks like the only way to get the front side lights working is to follow the method you outline here, correct. What about the rear side lights? Do the hazard lights work as normal on your build? I’m still going through the wiring to see if previous owner did any cutting/splicing.