57 GMC headlight and running light issue
 

Has anyone had issues like this I can pull the headlight switch out and the running light will work but then I pull it all the way out so the headlights turn on only the front running lights will turn off and the headlights will turn on and rear running lights will work. Does anyone know why or is this a factory that it does this.

Thanks for your time guys.

Re: 57 GMC headlight and running light issue
 

What switch are you using?
I purchased a replacement switch from a major vendor and it does the same thing and I they said it was the way it was designed.

I hooked front and rear to the taillight terminal so all are on at both switch positions

Re: 57 GMC headlight and running light issue
 

Ditto. I guess back in the day the front lights didn't come on with the switch all the way out. I just put a jumper on mine.

Bubba

Re: 57 GMC headlight and running light issue
 

have you checked the connections on the switch to ensure they are connected in the proper place (things happen over the years) and power is NOT coming through with h/l on? possible ground issue on the rad support where both circuits have a common ground? maybe the fuse/connections in the switch are toast right out of the box? front marker lights SHOULD come on with the headlights but not sure how that year of truck was wired back in the day.

I know the switches have built in fuses etc but have you thought about installing a couple of relays to run the different light circuits? that way the headlights and front and rear circuits can run independently of each other on different fused circuits and the draw will be less on the headlight switch. a good idea if you have a trailer plug as well just in case of a bad trailer circuit.

Re: 57 GMC headlight and running light issue
 

Back in the day the front "running lights" were actually called "park lights" and they were only on when the headlights were off.

:uhmk:

Re: 57 GMC headlight and running light issue
 

Hey everyone so they are just park lights and they only come on when you pull the headlight switch one pull so everything is working correctly it a the stock switch but I do like learning new things like this but I also found out that standard company makes a switch that look like the stock one and make it so the "park lights" come on when the headlights are on I ordered it today it should be in tomorrow I'll take a picture and show you guys tomorrow. I really like this forum because everyone is so helpful. Thanks guys keep on trucking huge swap meet this weekend in my town thank God the wife is working because I'm gonna get in trouble lol

Re: 57 GMC headlight and running light issue
 

Would like to see that switch, install the same as factory? Part number?
Thanks

Re: 57 GMC headlight and running light issue
 

The front "marker lights" are the parking lights, but they were used for events like going to a drive in theater, and not disturbing the moviegoers with your headlights on.
In 1963, it was determined that the turn signals could double as "marker lights, and the parking lights were turned on with the headlights.

If you want this for your early truck, there is a spare terminal on the headlight switch for the tail lights. Since that same switch was used for big trucks' marker lights.
Just move the parking light wire to the aux tail light terminal, and they will be on whenever the tail lights are powered, IE, anytime the headlight switch is on in any position.