Parking Lights stay on

[elorenzof]

Good morning everyone,

I have a 1970 C10, newly restored from the frame up. Putting on the final touches and little things that need to be completed.
I have an issue that i hope you all can help. I have used new M&H wiring harness(s) for the entire truck. Dash Harness, Engine Harness, Front Harness, Intermediate Harness to rear, and finally rear harness is all new from M&H. Also, have all brand new switching, headlight switch, Ignition Switch, brake light switch, etc... Everything is relatively "Plug and play"

My issue is that my parking lamps stay on at all times. Key on, or key off, ( i know its a different circuit) I have to disconnect the battery to get them to turn off. I thought it was an internal headlight switch problem, and i changed out the new headlight switch. We all know nothing is made like it used to be.

When i put the new headlight switch it was still hanging out of the hole in the dash and i tried it by pushing in the switch all the way in to have everything off and it worked! Parking lights went off. Pull the switch out one click, parking lights come on. Pull out two clicks, headlights / parking lights all work.

However, after i mounted the switch in the dash it appears it grounds thru the dash and now the parking lamps front, rear, side markers etc, stay on. so im back to what it was doing.

Can anyone shed some help i would greatly appreciate it.

Lorenzo

[Stanco]

Originally Posted by elorenzof

When i put the new headlight switch it was still hanging out of the hole in the dash and i tried it by pushing in the switch all the way in to have everything off and it worked! Parking lights went off. Pull the switch out one click, parking lights come on. Pull out two clicks, headlights / parking lights all work.

However, after i mounted the switch in the dash it appears it grounds thru the dash and now the parking lamps front, rear, side markers etc, stay on. so im back to what it was doing.

I suspect the problem is mechanical and not electrical. In other words something is preventing the switch from going to the full off position when installed in the dash.

You can test this by removing the switch from the dash and temporarily grounding it. If the parking lights remain off when grounded the problem isn't electrical.

[PbFut]

Could also be in the turn signal or emergency switch. Bad grounds do really funky things since it creates a back feed and that can travel up a completely unrelated device/path. Are you sure the radiator support is properly grounded and that the contact points of the front and rear housings are solid to ground? Newly painted surfaces can insulate the the grounding.

[elorenzof]

Originally Posted by PbFut

Could also be in the turn signal or emergency switch. Bad grounds do really funky things since it creates a back feed and that can travel up a completely unrelated device/path. Are you sure the radiator support is properly grounded and that the contact points of the front and rear housings are solid to ground? Newly painted surfaces can insulate the the grounding.

Thats a good point, I have had the core support powdercoated, as the frame. I will add a ground from the core support to the frame, and i have a new headlight switch as well. I have a ground strap from LMC. Yes, i will clean to bare metal on both the fram and the core support. I'm thinking that's what you said?

[elorenzof]

Originally Posted by Stanco

I suspect the problem is mechanical and not electrical. In other words something is preventing the switch from going to the full off position when installed in the dash.

You can test this by removing the switch from the dash and temporarily grounding it. If the parking lights remain off when grounded the problem isn't electrical.

It was the headlight switch. Just so you know, this was the THIRD HL Switch... However, I did do a ground after the fact from my Core Support to the Frame just as a because i can kinda thing.