Still no dome light
Grand Champion
Joined: Apr 2010
Posts: 5,011
Likes: 6
From: Meeker, CO
If you close the doors and switch the dome lamp off with the headlight switch, that circuit you're calling "dome lamp ground" is connected through everything in the dome lamp, overhead console map lamps, and door ajar circuits (which includes the Central Timer Module) to the positive terminal of the battery, while there is no ground at all being applied. Accordingly, that open circuit will be, must be, at battery voltage. Once you close one of those switches and current begins to flow, the voltage should then fall to very near zero. That's normal, as-designed operation, not a symptom of failure, and not power being "backfed" through a ground -- there's no ground there at all until you close one of those switches.
Since F13 is not supposed to be anywhere near that dome lamp/door ajar circuit, its presence or absence should have no effect upon that circuit. If someone's gone in there installing aftermarket goodies or attempting repairs by guess and by golly, all bets are off.
Thread Starter
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Professional
Joined: Dec 2011
Posts: 134
Likes: 0
From: Indiana
The behavior of electrons is not among the many, many things of which I am ignorant.
If you close the doors and switch the dome lamp off with the headlight switch, that circuit you're calling "dome lamp ground" is connected through everything in the dome lamp, overhead console map lamps, and door ajar circuits (which includes the Central Timer Module) to the positive terminal of the battery, while there is no ground at all being applied. Accordingly, that open circuit will be, must be, at battery voltage. Once you close one of those switches and current begins to flow, the voltage should then fall to very near zero. That's normal, as-designed operation, not a symptom of failure, and not power being "backfed" through a ground -- there's no ground there at all until you close one of those switches.
Since F13 is not supposed to be anywhere near that dome lamp/door ajar circuit, its presence or absence should have no effect upon that circuit. If someone's gone in there installing aftermarket goodies or attempting repairs by guess and by golly, all bets are off.
If you close the doors and switch the dome lamp off with the headlight switch, that circuit you're calling "dome lamp ground" is connected through everything in the dome lamp, overhead console map lamps, and door ajar circuits (which includes the Central Timer Module) to the positive terminal of the battery, while there is no ground at all being applied. Accordingly, that open circuit will be, must be, at battery voltage. Once you close one of those switches and current begins to flow, the voltage should then fall to very near zero. That's normal, as-designed operation, not a symptom of failure, and not power being "backfed" through a ground -- there's no ground there at all until you close one of those switches.
Since F13 is not supposed to be anywhere near that dome lamp/door ajar circuit, its presence or absence should have no effect upon that circuit. If someone's gone in there installing aftermarket goodies or attempting repairs by guess and by golly, all bets are off.
Registered User
Joined: Jan 2009
Posts: 24
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From: Southern MO
"The behavior of electrons is not among the many, many things of which I am ignorant."
The tone of this post is not something we tolerate here. Hence, it has been removed.
The tone of this post is not something we tolerate here. Hence, it has been removed.
Last edited by HeyYou; Apr 7, 2016 at 09:37 AM. Reason: Personal attacks.
Administrator
Joined: Apr 2010
Posts: 87,426
Likes: 4,215
From: Clayton MI
If pulling the power lock fuse interrupts the ground circuit for your dome light, then there is something wrong with the wiring in your truck. It really is that simple. The circuits, according to the wiring diagrams, are completely separate, there is no commonality there.
Grand Champion
Joined: Apr 2010
Posts: 5,011
Likes: 6
From: Meeker, CO
Let's just start at the beginning... Do you have a multimeter or at least a test light handy?
Does your chime sound if you insert the ignition key fully and then open the driver door? And does the halo lamp around the ignition switch illuminate as it should?
To start troubleshooting with a test light: First, ground the alligator clip end, and probe the lamp socket pins with the doors closed. One of them should illuminate the test lamp. Then remove the alligator clip end from ground, connect it to the battery positive terminal one way or another, and probe the other lamp socket terminal -- the test lamp should come on and go off when you open and close each door, and with the doors closed, when you turn on/off the dome lamp via the headlight switch.
Which one of those doesn't happen?
The cabling is a PITA to get at, but it's a simple circuit and we can at least determine where, generally, the fault lies pretty quickly. Tell us about the door dinger, halo lamp, and the dome lamp socket tests and we can go from there.
Does your chime sound if you insert the ignition key fully and then open the driver door? And does the halo lamp around the ignition switch illuminate as it should?
To start troubleshooting with a test light: First, ground the alligator clip end, and probe the lamp socket pins with the doors closed. One of them should illuminate the test lamp. Then remove the alligator clip end from ground, connect it to the battery positive terminal one way or another, and probe the other lamp socket terminal -- the test lamp should come on and go off when you open and close each door, and with the doors closed, when you turn on/off the dome lamp via the headlight switch.
Which one of those doesn't happen?
The cabling is a PITA to get at, but it's a simple circuit and we can at least determine where, generally, the fault lies pretty quickly. Tell us about the door dinger, halo lamp, and the dome lamp socket tests and we can go from there.
Record Breaker
Joined: Apr 2013
Posts: 1,815
Likes: 56
From: Alberta
know anyone with a full function scan tool? all these inputs can be verified in seconds with a scan tool.
if you want to grd the yellow wire...access the connector at the headlamp switch and use a jumper wire to grd
if you want to grd the yellow wire...access the connector at the headlamp switch and use a jumper wire to grd
Captain
Joined: Apr 2016
Posts: 647
Likes: 3
From: Alabama
Confusin' Fusin'?
I wonder if someone is confusing F12 with F13. F12 is for the dome light and f13 is for the door locks. Your wiring may have been messed with, as others who are trying to help are saying. Play nice!
Thread Starter
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Professional
Joined: Dec 2011
Posts: 134
Likes: 0
From: Indiana
Let's just start at the beginning... Do you have a multimeter or at least a test light handy?
Does your chime sound if you insert the ignition key fully and then open the driver door? And does the halo lamp around the ignition switch illuminate as it should?
To start troubleshooting with a test light: First, ground the alligator clip end, and probe the lamp socket pins with the doors closed. One of them should illuminate the test lamp. Then remove the alligator clip end from ground, connect it to the battery positive terminal one way or another, and probe the other lamp socket terminal -- the test lamp should come on and go off when you open and close each door, and with the doors closed, when you turn on/off the dome lamp via the headlight switch.
Which one of those doesn't happen?
The cabling is a PITA to get at, but it's a simple circuit and we can at least determine where, generally, the fault lies pretty quickly. Tell us about the door dinger, halo lamp, and the dome lamp socket tests and we can go from there.
Does your chime sound if you insert the ignition key fully and then open the driver door? And does the halo lamp around the ignition switch illuminate as it should?
To start troubleshooting with a test light: First, ground the alligator clip end, and probe the lamp socket pins with the doors closed. One of them should illuminate the test lamp. Then remove the alligator clip end from ground, connect it to the battery positive terminal one way or another, and probe the other lamp socket terminal -- the test lamp should come on and go off when you open and close each door, and with the doors closed, when you turn on/off the dome lamp via the headlight switch.
Which one of those doesn't happen?
The cabling is a PITA to get at, but it's a simple circuit and we can at least determine where, generally, the fault lies pretty quickly. Tell us about the door dinger, halo lamp, and the dome lamp socket tests and we can go from there.