LED Changeover - 1970 to 1972 Skylark & GS

Rule #1
Nothing ever turns out to be easy

So I pulled the tail light lenses, that part was easy! When (whoever before me) had the car undercoated, they went all hog wild and sprayed that stuff EVERYWHERE. It probably saved the car for the most part but getting that stuff off the lenses is a pain in the ***. The lens gaskets are also pretty much shot, so I had to buy a couple of those too.

Then...the taillight housings... All the chrome paint is pretty much shot so I had to remove the housings. Apparently the only way to get to the outer fasteners is to remove the rear corner pieces. Not too horrible, just 3 speed nuts covered with undercoating. Then one click at a time with the socket wrench to get the last 2 outer fasteners out, that was fun!

Now I need to clean off all the old chrome paint that is flaking off and do a fresh paint job on the housings, and while I'm at it, paint the silver trim around the lenses which has faded away to mostly red.

Tomorrow ill get the hose out and (carefully) try to blast the flaking chrome off and get some goo gone to get the undercoat off the lenses.

Just swap the bulbs to LED's they said....rant over!

 

To be fair, it would have been required if you just wanted new regular bulbs to be seen better.

 

5 years ago I replaced all the bulbs with silver star sylvania and neglected to do anything about the existing problem. It's my own damn fault for being lazy. I just forgot how bad it really was!

It's time to pay the piper and do it right.

 

4 of my sockets have roached out bulb contacts....

The parts illustration I have shows the stop,turn,signal and reverse as all the same number (8903283) but that can't be right for the reverse socket. The stop,turn,signal are 3 wire (double contact) and the reverse is 2 wire (single contact).





So i (think) i got a good cross reference for the 3 wire (stop,turn, signal) signal:
https://www.wiringdepot.com/store/p...ail-w/-Weatherproof-Seal-1969-Newer-1-Pc.aspx

How do I find the 2 wire reverse socket? Does anyone have the cross reference number?

 

Most people use a 2-element 1157 bulb in the reverse position. You can use a 2-element socket and only wire up the brightest filament.

Here's a socket on the same site you listed.

https://www.wiringdepot.com/store/p/497-JT-T-2586F-2-Wire-GM-Single-Contact-Back-Up-Cornering-Turn-Light-Socket-Pigtail-1972-Newer-1-Pc.aspx

I found some 1156-style sockets on Amazon but I don't know if they will fit in our taillight housings. I suspect they can be massaged to fit.

Have a look at these to see if they might work. I don't have a bulb socket in front of me to compare. They look pretty close.

Amazon.com: Dorman 85827 Socket Assembly for Select Pontiac Models: Automotive

If not, maybe something like this can be adapted.

Amazon.com: 1156 7506 BA15S Adapter, Bonlux BA15S Bayonet Socket Wiring Harness Connector for Turn Signal, Brake Light, Tail Lights or LED Bulbs Retrofit, 2-Pack: Automotive

 

The correctness police are gunna get you guys...

 

I think the one Greg linked from the wiring depot is correct, even though it says 72 and up.

 

I began my LED adventure last year around the time I put my car in the garage for the season. My 68 Custom bulb swap was pretty straight forward. So far I swapped out side markers, trunk , under hood, front courtesies, heater controls , auto meter gauges and reverse lights. All of these work and I like the look. Moving on I swapped out the 1157’s in the front and rear . The amber fronts and rear running lights look sharp and red LED brake lights are a marked improvement. So far the only “ glitch “ is no directionals or flasher’s I changed the flasher to one with the external ground wire. I checked the voltage at taillight sockets with the directionals on and have 0 volts. Where should I be checking next ? Thanks again for your response’s

 

Usually, when a normal flasher is used, the turn signals will stay on since they don’t draw enough to trip the blink action.

Swap an old one in and see if you get voltage.

 

Only getting voltage when running lights and brakes are on 12.3V. Before the swap directionals/ flashers worked with no issues. Will take some pictures later when sun goes down.

 

Almost sounds like an issue at the flasher. You sure that it's pushed in all the way? Check for 12V at either of the pins with the key on?

 

I’m getting 12 V out of the pink wire that plugs into flasher

 

Some pictures of what I have working . Looking for a LED bulb for rear armrests .

 

Update , this is the flasher I ordered for the LED’s along with the rear LED bulbs . Out of curiosity I plugged the new flasher into where the flasher for the hazards was and after attaching the ground strap the hazards are working. When the new flasher is plugged into the pink/ purple plug for the directional s nothing. I’m showing 0 Volts in all directional sockets .As I said in my previous post the pink wire is a constant 12 V . What should I be checking for next ?

 

That is perplexing. Mine, when grounded and plugged in, blinks the lights as I'd expect. Did you try your old, non-LED compatible flasher to see if all the lights come on and stay on instead of flashing?

 

I'm no expert at this, but I think you ruled out an issue with the flasher.

I would think that the next thing to check would be what provides the signal to activate the flasher (turn signal switch?) or possibly a bad ground somewhere. I didn't run into these issues when I did my LED bulbs in the 69.

Here is a PDF of the wiring diagram for the 1969. I would think that it applies to the 68 as well. This may help you figure it out, if you don't already have it.

 

Yes I tried the old one & got nothings working.... figured the lights would just stay on.: but no volts at the sockets it

 

So, 12v in and nothing out? Is the socket malfunctioning?

You should be able to jump that blinker socket with a test wire to get the bulbs to light up with the blinker turned to left or right. It might be obvious but I'm going to ask. You do have the key is in the run position, right? Flashers and parking lights work all the time, blinkers only when the key is on.

 

Good idea... I didn't think of that. Check fuses as well. They seem pretty sensitive to a wrong contact somewhere at any given time.