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Headlight Switch - Circuit - Ground
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Fleet Mechanic
Joined: Aug 2005
Posts: 1,462
Likes: 74
From: Hartford, AL
Headlight Switch - Circuit - Ground
Is the only ground for the headlight circuit at the side marker light/headlight ground? Does the headlight switch ground itself to the metal dash or the dimmer switch ground itself to the cab floor?
Also if anyone has a picture of the routing of the wiring harness that connects the headlight and side marker light that would be much appreciated.
Also if anyone has a picture of the routing of the wiring harness that connects the headlight and side marker light that would be much appreciated.
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
The only grounds in the headlight system are against the radiator support (front parking, marker, high/low beam) and bed sheetmetal (rear marker lights). The headlight and dimmer switches only interrupt power.
Hotshot
Joined: Apr 2009
Posts: 14,333
Likes: 247
From: Stanley, VA
Neither the headlight switch nor the dimmer switch are grounded. The circuits they power are eventually grounded but the switches themselves aren't.
Do you want an actual photograph of the wiring or a schematic?
Do you want an actual photograph of the wiring or a schematic?
Hotshot
Joined: Apr 2009
Posts: 14,333
Likes: 247
From: Stanley, VA
.The Pumpkin's a '73 F100 2WD.
Thread Starter
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Fleet Mechanic
Joined: Aug 2005
Posts: 1,462
Likes: 74
From: Hartford, AL
Those are PERFECT. Thank you so much! I have lights now.
One other question totally unrelated to the headlights, but what about the ignition switch. Does it have to be ground to the metal dash? According the Ford Shop Manual that I have when testing the ignition switch it is saying you must ground the ignition switch body against metal. I no longer have a metal dash (now wood and fiberglass) is why I ask these questions.
Also.....
"These are some 'before' pictures I took when I tore down the Pumpkin. I haven't gotten it back together yet so I don't have any 'after' pictures .
The Pumpkin's a '73 F100 2WD."
Me too, that is why I asked about pics, it has been so long since I took mine apart (also a '73 F100 Ranger 2WD). I modified inner fenders along with a bunch of other stuff so I couldn't remember how it was originally routed and where the grounds connected. Lesson to self. Take more pics when you have something apart for years.
Thanks!
One other question totally unrelated to the headlights, but what about the ignition switch. Does it have to be ground to the metal dash? According the Ford Shop Manual that I have when testing the ignition switch it is saying you must ground the ignition switch body against metal. I no longer have a metal dash (now wood and fiberglass) is why I ask these questions.
Also.....
"These are some 'before' pictures I took when I tore down the Pumpkin. I haven't gotten it back together yet so I don't have any 'after' pictures .
The Pumpkin's a '73 F100 2WD."
Me too, that is why I asked about pics, it has been so long since I took mine apart (also a '73 F100 Ranger 2WD). I modified inner fenders along with a bunch of other stuff so I couldn't remember how it was originally routed and where the grounds connected. Lesson to self. Take more pics when you have something apart for years.
Thanks!
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MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
Yes, the ignition switch must be grounded. This is to support the PROVE-OUT mechanism of the ignition switch. This is what causes the BRAKE light to briefly light as you turn the key toward START to tell you the bulb is good.
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Hotshot
Joined: Apr 2009
Posts: 14,333
Likes: 247
From: Stanley, VA
Heh, heh. Fortunately I had an ex-brother-in-law who I watched take stuff apart "just for a little bit" and then never remembered how it went back together. To me, a camera made sense.
I'm just glad they invented digital cameras. I'd go broke on developing.
I'm just glad they invented digital cameras. I'd go broke on developing.
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