WIRING QUESTION
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Mountain Pass
Joined: Oct 2023
Posts: 163
Likes: 59
From: Kaslo, BC, Canada
WIRING QUESTION
I am testing the wiring harness lighting circuit prior to reinstalling the radiator support. When I meter the headlight socket between the black ground wire and the respective high and low beam pin I am seeing 12v on Hi-beam pin and 11.5V(ish) on the low beam pin. plugging in a known good headlight produces no light at all on either side. Additionally the only dash light I am seeing is a dim left turn indicator. The dim turn light indicator is a tell tale sign of a bad or missing ground resulting in back feeding by some mysterious path. So my question is where are the wiring harness grounds typically physically located on the truck. There is no lighting in the back end either.
Anyone have any insight??
Anyone have any insight??
Cargo Master
Joined: Jul 2005
Posts: 2,309
Likes: 364
From: Kansas
the lighting circuit grounds connect to the radiator support. Where are the ground wires currently connected? sounds like your radiator support isn't installed yet? if that is the case, simply hook the ground wires directly to the negative battery post for testing the wiring itself...
Moderator & parts slinger
Joined: Feb 2007
Posts: 50,096
Likes: 5,757
From: S/W Missouri, Polk county
Did you turn (rotate) your head light switch fully counterclockwise, to turn your dash lights up to full bright? If you go to the bump that is full bright on the dash lights, past the "bump" you turn on your dome light with the doors closed.
Hotshot
Joined: Feb 2004
Posts: 10,728
Likes: 2,584
From: The Shenandoah Valley
X2, sounds like you using a probe test light and if you clip that ground wire clip to the battery neg, you'll get full battery volts probing the head light socket .... but that known headlight is grounded through the harnes to the rad support which has no good ground unless mounted.
12v or 11.5V(ish) are themselves low for a good battery.
12v or 11.5V(ish) are themselves low for a good battery.
Thread Starter
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Mountain Pass
Joined: Oct 2023
Posts: 163
Likes: 59
From: Kaslo, BC, Canada
YEs With help from my buddy who is a trained electronics technician I have determined that I spent the entire day chasing a "Phantom Ground" situation. Live and learn. Good thing my labour rate is only three square meals a day from the Missus.
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