1972 Electra: no turn signal indicator light

I just bought a 72 Electra and find the left turn signal control light in the dash doesn´t come on, neither when setting the turn signal nor the hazzard lights. All exterior lights do what they are supposed to do.

Of course I checked the bulb, and while it´s a bit of a PITA in reaching up from the footwell and pulling out the twist socket, it can be done. I changed the #194 bulb, nothing. I checked the old bulb on the bench, lights up. So definately not the bulb!

Does the 72 Electra have a printed circuit board? And how do I pull out the instrument cluster to check if the conducting paths are bent or broken? Any other idea what could cause the problem?


While I was under the dash I found an empty socket dangling on two wires, one of them PPL in color, near the left turn signal indicator light socket. I put in a #194 bulb and turned on all pwr switches I could think of, but the light never came on. I have a (Factory?) Service Manual and the only light I found in this area was "Rear Defogger Control" or similar. My car doesn´t have this. Did they already put in "all purpose" harnesses back in the days and left unused what wasn´t needed?

 

One great video, thank you for this! Lots of helpful advice and hints, one of them, that the dash indicator lights have a tendency of NOT working correctly, when the battery is low. I had to jump start the car the other day after having it sit for a couple of weeks and not have had the chance of driving since, so I´ll make sure the battery is fully charged before I pull out the dash. Maybe the problem goes away with a fully charged battery all by itself.

One other hint in the vid is (at 17 min.) the unused socket on PPL wires, apparently being for the optional rear defogger the Rivi in the video is not equipped with. Same with mine, I belive. Not sure if the light in the clock works, I´ll check next time I´ll get to the vehicle.

The external bulbs are ok, I changed the front turn signal bulbs from white to amber, so they are new, but the old bulbs for indicator and turn signal had been working before. Yes, I am aware of the constant light on blown filaments, thanks for reminding me anyways.

FWIW, I did have to replace the 20A glass fuse for CTSY as the int. lights were not coming on. They did immediately on the new fuse.

 

Luv to May not be the best ones, but you get an idea.






















It´s a SC car. The PO had the vehicle taken apart and had the frame, suspension and body repainted, tank replaced, brakes gone thru, top engine overhauled and painted. I have receipts and invoices back until the mid 80´s, two built sheets, the owner´s manual, warranty card, etc. While I don´t claim that the car looks brand new but, boy, it looks veeery close.

 

Thank you for the additional info! Yes, in line with what I know about the car.

Now, although mine came with color code 28 Royal blue and #631 interior, the re-paint apparently was done in some other blue, darker and metallic compared to original. I´ll have to flick thru the bills to see if I can find out what it is. Bearing in mind that I had to replace the old tires that came with it and that I will have to replace the headliner in the near future and some smaller things, I paid a lot less and guess I got a hell of a deal.

As for the fuel gauge, yes, I´ll have to check on the ground.

 

Uhum, I have those other rims on my 67 LeSabre and I luv `em...

 

No and needles.

 

That's a nice looking Electra! Have to applaud your choice of ride

Bob

 

Thx

BTW, I don´t have the wiper delay and I am not sure, if this was an option at all this year. Anyways, it´s giving me trouble and I will describe in another post.

 

Ok, I finally got around addressing the non-working turn signal indicator light. Matter of fact, this was the last of the problems I planed to address, but hey. I dug into the dash because the dash illu wouldn´t work either.

Now, I can absolutely confirm that tracing defectives in electrical systems of vehicles new to me sucks! I spent days looking at wiring diagrams and assembly schematics, trying to understand which wires light what, which elements belong to each other and how several faults might have the same cause, e.g. bad ground connection.

Yesterday I took out the driver seat, crawled under the dash backwards and tried to identify wire colors, harness routings, connectors, etc. I wound up finding connectors that were not plugged in and bulb sockets not carrying bulbs, making me think I had found the culprit. Wrong! This only brought me back to the ASM, just to find that GM apparently already back in the days used universal harnesses for various models, no matter the actual accessories on the car, i.e. those connector on my vehicle were unconnected for a reason. I did find all grounds ok and no loose wires to solve my problem.

I ended up taking out the speedo cluster out of mere desperation, although convinced, all three bulbs of the cluster illu don´t burn out at the same time. And they didn´t! When I looked at the printed circuits of the speedo cluster I found the copper leads of all three cluster illu bulbs AND the left TS indicator lamp all black, full of dirt, grime, corrosion, whatever. Only those, the warning lights all looked ok and worked fine. I took out ALL twist sockets one after one and used sandpaper to clean up the connection points. I did the same with the contacts where the cluster connector meets the board. Before reassembly and while on the bench, I put +12V and ground to the two relevant copper leads on the printed circuit board et voila, there was light!

Now, reassemly is another story! It took me at least 30 min. to plug the cluster connector back into the slit and get the tabs to lock. Problem is, the cluster needs to be tilted upwards and to the right and your left hand needs to go under the cluster, grab the connector, whose wires are too short, and the connector needs to be put in the board without seeing and the connector meets the board at an angle and my hand is too big and my fingers too short and the space too little and the wires are too short.... You get the idea.

Anyways, when the damn connector was finally back in - lights! And left TS light. Job done!

While I was in there, I also used sandpaper on the three threaded copper studs of the fuel gauge (you guessed it - also corroded) and the tabs they go into on the printed circuit board. I was hoping the fuel gauge would come back to life - but no, not at this moment. BUT: when I afterwards grounded the tan wire in the trunk, the needle walked all the way back to the left! Hooray! So at least in theory the gauge should get back to work when I replace the sending unit I have coming in later this month.

Here is the only downside: when I stuck the speedo board back in, I must have missed the square speedo cable, the speedo doesn´t work. I had the cable collar back in it´s metal bracket but must have missed it anyways.

Is there a surefire way to get this matched up without taking out, putting in, checking the speedo needle on the road, taking back out and put back in half a dozen times?

 

Not my post, but I want to say cool idea. Thanks Larry.