Just joined? Please introduce yourself.
Classic Edge Designs, LLC Prime Custom Cars, LLC MadMooks
Page 2 of 2 FirstFirst 12
Results 11 to 14 of 14

Thread: Dome lights

  1. #11
    Registered Member 55 Rescue Dog's Avatar
    Join Date
    Nov 2015

    Member #:2775
    Posts
    825
    Probably because they could just use a simple one wire self-grounding switch, instead of a 2 wire switch like the glass bodied Vette which still needed 2 wires to the light too. Plus unlike newer cars you didn't need a computer just to simply light a bulb. It was too easy the old way, which I miss now. How many relays/switches/electronics/connections/wiring etc. do you want to troubleshoot when something doesn't work, and you have to rip the car apart to fix it? It would be my worst nightmare troubleshooting a newer
    Chevy like my 13 Tahoe, or 97 C5 that can have many random issues. The simpler the better IMO, which is the beauty of a stock trifive.
    Last edited by 55 Rescue Dog; 01-07-2019 at 04:10 PM.

  2. #12
    Registered Member chevynut's Avatar
    Join Date
    Nov 2011

    Member #:115
    Location
    Fort Collins, CO
    Posts
    9,628
    Quote Originally Posted by 55 Rescue Dog View Post
    Probably because they could just use a simple one wire self-grounding switch, instead of a 2 wire switch like the glass bodied Vette which still needed 2 wires to the light too.
    Like a 2 wire switch is that complicated? LOL. They already had them tooled for the Corvettes, and they NEEDED to run two wires to the light on those cars to ground the dome light even if they switched power. They didn't need to on the steel bodied cars and it goes against electrical design conventions for everything else.....where power is switched.

    How many relays/switches/electronics/connections/wiring etc. do you want to troubleshoot when something doesn't work, and you have to rip the car apart to fix it?
    As many "relays/switches/electronics/connections/wiring etc." as I need to get the functions I want. My Nomad will have automatic on headlights, retained accessory power, and dome light soft dimming because I want those things. New cars have them and I like the features. And it's pretty simple to do with the DD module and the wiring isn't that complex. Plus I'll have a lot more "complicated" electrical things like EFI, keyless entry, fan control, electronic A/C control, power windows, power vent windows, power door locks, electric hood release, digital self-dimming mirror, and more. If you don't want those things stick to the simple stock stuff that you have the ability to wire and troubleshoot.

    You keep drifting off-topic, which is WHY GM and others used switched ground to turn on dome lights. On a tri5 you save ONE connection by doing that. On a stock tri5 car you have one connection to each door switch, two connections to the dome light, and one to the headlight switch. That's a total of 5 connections. If you switched power you'd have one connection to the headlight switch ( if the switch was designed that way), two connections to each door, and one connection to the dome light for a total of 6. Getting one less connection while using more wire is hardly justification, imo, for changing the way the circuitry works for this one application. But maybe those push-on connectors were big bucks back then.
    56 Nomad, Ramjet 502, Viper 6-speed T56, C4 Corvette front and rear suspension

    You can see my 56 Nomad build here http://www.picturetrail.com/chevynut

    For affordable C4 Corvette Suspension conversions for your car, visit http://www.classicedgedesigns.com

    Other vehicles:

    56 Chevy 2-door BelAir sedan
    56 Chevy 210 4-door sedan
    57 Chevy 210 4-door sedan
    1961 Willys CJ3B Jeep
    2001 Porsche Boxster S
    2003 Chevy Silverado 2500 HD Duramax

  3. #13
    Registered Member scorpion1110's Avatar
    Join Date
    Jul 2017

    Member #:3477
    Location
    Mount Airy, MD
    Posts
    128
    Quote Originally Posted by chevynut View Post
    Like a 2 wire switch is that complicated? LOL. They already had them tooled for the Corvettes, and they NEEDED to run two wires to the light on those cars to ground the dome light even if they switched power. They didn't need to on the steel bodied cars and it goes against electrical design conventions for everything else.....where power is switched.



    As many "relays/switches/electronics/connections/wiring etc." as I need to get the functions I want. My Nomad will have automatic on headlights, retained accessory power, and dome light soft dimming because I want those things. New cars have them and I like the features. And it's pretty simple to do with the DD module and the wiring isn't that complex. Plus I'll have a lot more "complicated" electrical things like EFI, keyless entry, fan control, electronic A/C control, power windows, power vent windows, power door locks, electric hood release, digital self-dimming mirror, and more. If you don't want those things stick to the simple stock stuff that you have the ability to wire and troubleshoot.

    You keep drifting off-topic, which is WHY GM and others used switched ground to turn on dome lights. On a tri5 you save ONE connection by doing that. On a stock tri5 car you have one connection to each door switch, two connections to the dome light, and one to the headlight switch. That's a total of 5 connections. If you switched power you'd have one connection to the headlight switch ( if the switch was designed that way), two connections to each door, and one connection to the dome light for a total of 6. Getting one less connection while using more wire is hardly justification, imo, for changing the way the circuitry works for this one application. But maybe those push-on connectors were big bucks back then.
    Serenity Now. Say it fast several times. Works well for me
    Scorpion1110

    Rides:

    1955 Chevy 2-door Wagon
    1970 Honda Trail 70

    I lost my best friend on 10/3/2018. Rest in Peace Dear Lucy. I will miss you.

  4. #14
    Registered Member WagonCrazy's Avatar
    Join Date
    Mar 2012

    Member #:530
    Location
    Santa Clarita, CA
    Posts
    1,060
    I did 15 minutes of google searching "why did General motors use switched ground to turn on dome lights" without anything conclusive coming up.

    I suspect its because they had a supplier (partner company owned by the GM parent) that made these 1 pole door switches from way back, and with the tooling cost...just consistently designed all their cars with this switched ground wiring plan. It was probably low hanging fruit to try and redesign it for a dual pole switch.

    Just wire it the way you want to (with switched 12v power) and move on to funner things Laszlo.
    1957 Nomad- LS1/T56 on C4 chassis- [URL=http://s78.photobucket.com/user/pcardey/library/57%20Chevy%20Nomad%20wagon[/URL]

    1959 Fleetside Apache 1/2 ton, shortbed, big window- [URL=http://s78.photobucket.com/user/pcardey/library/59%20Apached%20Fleetside%20Big%20Window%20Shortbed[/URL]

Page 2 of 2 FirstFirst 12

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •