The Stovebolt Site Forums The Shop Area The Electrical Bay GMC Truck - Indicator light colors

I have a bit of a dumb question, but in my defense I'm a Millennial who has had more time around old farm tractors than old pickups.

So on my 1959 GM 2.5-ton dump truck, there are two large indicator lights on the dash (three if you count the red generator indicator light, but that one is directly labled), one with a green lens, and one with a red lens.

I am assuming the green one was for the turn signal flasher, and the red one is for the High-beam indicator?

I'm going by the Chevrolet truck owners manual, which has the triangular cluster, and not the individual guages like my big bolter.

Can you post a picture? I thought all the sizes of trucks used the same cluster and it has arrows for the turn signal lenses. My 58 and 59 are both 3200s, so I could be wrong about the larger ones using the same cluster.

Edit: Do you have a GMC? Because they were a very different animal. If you do, I would recoommend specifying that in the post title.

The Chevrolet lenses are: a left and right green for turn signals, red for high beam, those are the only colored lenses on the '55 - '59 Chevy cluster, I have no experience with the GMC. Can you trace the wires and find out what might energize them?

GMC is as you expected Puffie. The red indicator goes on the left side and is the high beam indicator. The green goes on the right and indicates for both left and right turn signal. It is connected to the "P" (Pilot) connector on a 3 terminal flasher such as a DOT 550.


My 57's dash (before it was totaled:

Thanks for the confirmation. I do have the wiring diagram from the service manual, so I could see the function of the indicator lights, or 'tell-tales' as the diagram put it, but it didn't say what lens color they were!

The green lens was missing out of my turn signal indicator. No one repops it. I ended up cutting a piece from a plastic Sprite drink bottle (Mountain Dew bottle was too yellow). It still passed too much light, so I added another piece of foggy plastic.

Hmm, You can get transparent green acrylic sheet off of Amazon (you can also use SendCutSend to get them to cut the acrylic into to the disc), and there are layers of plastic found inside flat-screen TVs and Computer monitors used to evenly diffuse light.

Alternatively, the lens could be 3D printed using translucent green PETG - the mottling caused by the extruder nozzle would probably work as a diffuser.

Now, yes. Not 30 years ago when I redid the dash on my '57 1/2 ton.

Note the 270 degree oil pressure gauge. It was only on big trucks, as was the ammeter.

The tach is a Sun SuperTach II that originally had a 270 degree, 8000 RPM swing. I refaced it using a set of GMC dash decals and an Xacto knife. Making it run 4000 RPM at 270 degrees only involved switching it to 4 cylinder mode.