VCCA Home Forums TECHNICAL - 1945 AND NEWER 1949-1954 Interior turn lights

I’m back with another question for my 1954 Chevy 210. I have the turn signals working but when they blink, both interior lights in the dash flash rather than just the one in the direction flashing. I have a new wiring harness from Rhode Island wiring. The rest of the harness is working correctly best I can tell.

Thanks in advance for considering my query.

Frank

There's a wire in the wrong spot. My '53 did that until we found a blue wire disconnected. Plugged in back in and all was good. I'm not the one who crawled under the dash to reconnect it so I can't tell you exactly where it is but from my vantage point it looked to be directly above the steering mast and close the the firewall.

I’ve been under the dash and I think everything is connected. I’m guessing something is in the wrong place. Following the wiring diagram I cannot place the problem. It is hard to follow the wires under the dash. If I was only younger - more flexible or less weighty. It might help. I’ll try up under the steering mast again.
Thanks!

Hi Frank,

I agree that this working under the dash gets more difficult as we achieve seniority in life! And troubleshooting a problem like this is frustrating enough.

My thinking is that there are 4 potential reasons for the problem.

- As Tiny has noted possibly something is not connected correctly. One way to investigate that is to disconnect things that are easy to reach and observe what difference in behavior that makes. For example, remove the right front bulb and see what happens. With all the bulbs installed disconnect the wire to one of the indicator lights and watch how the other behaves. Also, make sure that the shared brake light/turn signal function works as expected.

- There is a bad ground somewhere in the whole system. I will never be able to understand the weird feedback loops that can create.

- One of the filaments for the turn signal in a bulb is burned out.

- Unfortunately maybe the wiring harness has an error in it.

There was a thread a few months ago where somebody was trying to get these to work on a 54 that had been 12v converted, It is time to consult a wiring diagram. This problem is a bit more confusing than it would at first seem.

IIRC the indicators do not ground through their housings like you would expect. On a "normal" system the dash indicators would connect to the FRONT signal lights, and just be grounded. These grounded through the third pin in the flasher IIRC. The third pin in the flasher is NORMALY used a power lead (not a ground) for a dash indicator when there is only one dash indicator for both sides.

This may be some sort of scheme to make the dash indicators misbehave in some way when there is a signal bulb out.

It may even be normal for both to flash. Does anyone remember?

The first thing I would do is make sure it has the CORRECT flasher.

Anybody got a wiring diagram?

I have the same trouble 1954 210( both lights blink) i have 12v system also. please let me know what people come up with..
you right about working under the dash.i'm 80 if i get on my head i might never get back on my feet..lol

The old car manual project has wiring diagrams that you can download.

The old car manual project has wiring diagrams that you can download.

Thanks for the info. Gives me some other leads. At this point everything is connected. Will have to trace the wires back to the front lights. The inside bulbs look good. I do have a good wiring diagram.
Thanks, Frank

Well, following along with the almost unreadable diagram....

http://chevy.oldcarmanualproject.com/electrical/wiring/images/54car1.jpg

A "normal" 6 volt system works as follows: There are 3 pins on the flasher. One is power (apparently switched ignition power coming from a fuse mounted on the gas gauge on this car). One sends voltage from the flasher to the turn signal switch. The third pin is for an single indicator light, such as seen on the "Guide 6004" switch used on the 51 chevy and a few other things. Since there is only one indicator, and it blinks for either side, it has to have it's own separate flashing voltage supply from the flasher.

If there were 2 indicators instead of one, you would just connect each dash indicator to it's matching front signal. Not the rear signals, because if you connected the dash indicators to the rear signals, they would come on with the brake lights. You don't want that.

If you look at the diagram, the dash indicators are connected to the front signals as per normal, but, instead of grounding the dash indicator bulbs at the sockets, they ran them back to the third pin on the flasher, via a black wire. It really doesn't make much sense. Maybe it is supposed to do something odd to alert you when a bulb burns out?

It seems to me that in a left turn, both connections to the "left" dash indicator would be hot, and it would not come on. Meanwhile the right dash indicator would "find" a ground through the right signal light bulbs, and it would flash. I suspect Chevrolet just reversed the positions of the right and left indicators in the dash to make that appear normal.

It also seems to me that if you are not running a stock flasher due to a 12v conversion or whatever, you would have to ground the black wire (after carefully verifying it goes to the 2 dash indicator bulbs!) instead of connecting it to anything on the flasher. You would probably then have to reverse the positions of the indicator bulbs in the dash.

So I would cut the black wire at the flasher and ground it.. ground the one from flasher or the one going to the lights ???

Assuming you have a standard 12 volt 2 pin flasher now, and everything else works, there should be an empty slot in the flasher socket, right?

I think that wire needs to be grounded.

To double check, that wire should go to both dash indicators, right?

The wiring diagram says its black, but I would double check before changing anything.

Well we figured it out. After lots of trial and errors. The grounds to the flasher had no effect. On or off. Ended up running a wire from the front indicator light to the interior indicator and letting the dash ground the light. The indicators now flash correctly in the dash. Exterior light flash and the brake lights work correctly. Wow what an ordeal. Thanks for everyone’s help and suggestions.

Glad you got it sorted out!