1. Welcome To GMTruckClub.com!

    The #1 Chevy Truck Forum Online
    Online since 2004, we are the #1 Chevy Truck & SUV forum and user community. If you have any questions about your Chevy or GMC Truck, SUV or Crossover, or just want to connect with other GM owners and enthusiasts around the world, you've found the best place on the internet to do that.

    Join Today ~ It's Free
    Registering is Free and Easy! Hope to see you on the forums soon!

Illumination wire?

Discussion in 'Lighting Discussion' started by SurrealOne, Jan 20, 2013.

Random Gallery Photos

  1. Enkeiavalanche

    Enkeiavalanche Moderator 1000 Posts 100 Posts

    Gotta say those are some Nice looking Switches.....
  2. zigger215

    zigger215 New Member 100 Posts

    It's not a "reverse ground". That doesn't even exist. It's a negative trigger meaning the power is constant but the impedance to ground fluctuates which causing the dimming in the lights. The symbol you're lookin for is "-". Just like our parking lights.

    Having worked professionally in the mobile installation industry and now as an IBEW wireman who has done tons of PLC installations, I can say they are nothing like cars....
  3. SurrealOne

    SurrealOne Former Member 1000 Posts 100 Posts

    Pardon my fumbled terminology.

    Pikey, I'll let you know when I test -- should be this weekend, weather permitting.
  4. Pikey

    Pikey Moderator Staff Member 1000 Posts 100 Posts


    I looked at the diagram again and it does not have any indication. I also looked at the parking light circuit diagram. It did not indicate a negative trigger either. Maybe the publisher "forgot" that part.
  5. zigger215

    zigger215 New Member 100 Posts

    Pikey I can tell you from years and years of experience that these trucks have many "negative trigger" circuits, park lights being one of them. Apply 12v to the grey/black wire on the switch and watch the free fireworks show...
  6. zigger215

    zigger215 New Member 100 Posts

    image-3756424970.jpg
    There you go, that's what a negative trigger looks like on direct wire. This is a complete schematic (way more in depth than a Haynes book) for a 2004 silverado.
  7. Pikey

    Pikey Moderator Staff Member 1000 Posts 100 Posts

    Oh, I am not doubting you in any way. I am just stating that my manual does not indicate the (-). I would always use a multimeter to figure out what was going on before i attempted any mods/repairs on an electrical system. I have seen way too many inconsistencies in wiring diagrams to trust anything 100%
  8. zigger215

    zigger215 New Member 100 Posts

    That's also pretty dang true. Always double check with a meter, I second that. I will say, GM has been awesome with their consistency on our trucks, I always loved working on our trucks when they came in the shop. I always knew what I was getting good or bad
  9. SurrealOne

    SurrealOne Former Member 1000 Posts 100 Posts

    I decided to go for a connection at the dimmer switch in the cab just because it's a place I knew I could easily probe. After removing my sound deadening material, cutting new material to fit (for when I finish), and probing/testing with a multi-meter, here's the verdict:

    The wire (at the dimer switch) is brown with a white stripe and is NOT a negative trigger.
    Last edited: Jan 27, 2013
  10. Scooter

    Scooter New Member 100 Posts

    Hey Zigger what app is that on your phone?

    Hey surreal I always love your work, I know you said 85 bucks for just the four switches but what did the whole setup run you. And would you be willing to do another similiar?

Share This Page