Dome lamp wiring

[FFRKing]

I’m wiring my ‘68 using an EZ wiring 21 circuit harness. All of the original wiring was pulled out and a spliced up nightmare.
So far, everything is going well and I’m wiring in the dome lamp. I was able to salvage the original harness for the door dome lamp switches. I am only able to bench test the switch and found out that one switch I had was bad. I have one from a parts truck that seems to function correctly.
My problem is wiring in the dome lamp power feed from the EZ harness. I’m using an ohm meter to figure out what goes where on th switch. I am also using the truck wiring diagram. Everything works except for when I want to turn on the dome lamp by rotating the light switch knob all the way to the left. Does rotating the switch all the way to the left provide the ground to turn the light on? If so, then I think I’m done. Once again, there is no power applied at this point as I’m still wiring things up.
I do have the Ron Francis wiring harness completely installed to run the 2006 4.6 3V. If I would have looked into it more, a 12 circuit harness would have been more than enough since a few of the functions are controlled by the RF harness.
Thanks

Chris

[basketcase0302]

"FFRKing"]I’m wiring my ‘68 using an EZ wiring 21 circuit harness. All of the original wiring was pulled out and a spliced up nightmare.
So far, everything is going well and I’m wiring in the dome lamp. I was able to salvage the original harness for the door dome lamp switches. I am only able to bench test the switch and found out that one switch I had was bad. I have one from a parts truck that seems to function correctly.
My problem is wiring in the dome lamp power feed from the EZ harness. I’m using an ohm meter to figure out what goes where on th switch. I am also using the truck wiring diagram. Everything works except for when I want to turn on the dome lamp by rotating the light switch knob all the way to the left. Does rotating the switch all the way to the left provide the ground to turn the light on? If so, then I think I’m done. Once again, there is no power applied at this point as I’m still wiring things up.
I do have the Ron Francis wiring harness completely installed to run the 2006 4.6 3V. If I would have looked into it more, a 12 circuit harness would have been more than enough since a few of the functions are controlled by the RF harness.
Thanks
Chris

Chris,

If you are using original switches as stated on the doors is doesn't matter which terminal there gets the 12 volt "+" wire from the power source, (as it is a single pole switch that simply closes the circuit to illuminate the bulb).
The headlight switch is basically the same thing, (a single pole switch) that sends 12 volts "+" to the bulb to illuminate it. The switches are a know fault so if your working with an older switch, (I've even seen many for our trucks come out of the box faulty) it is probably a bad switch.
And yes the dome light bulb gets the 12 volt positive power from the headlight switch or the door switches and the housing grounds to the sheet metal of the cab.
An easy upgrade to our bump era trucks is to replace the wimpy known to be problematic door light switches with the dent era, (with the pigtail harness from the same). You'll forever be glad you did and no longer be cussing your dome lamp for faulty switches.
Here's the schematic on it that might help:

[FFRKing]

Jeff,
Thanks for the reply. I have that diagram but somehow just noticed in the top right corner of the box that says Lighting Switch is the switch internal to the light switch that closes between terminals 53 and 54. This obviously is the dome lamp “on” switch when the light switch knob is rotated to the left.
I used the harness out of my ‘68 parts truck for the door switches, but picked up a pair of switches and plugs from a salvage yard from a newer Ford. I don’t remember what I pulled them from, but they are a much sturdier feeling switch with a very tight fitting plug and socket. I tested just the harness while on the table with a battery and everything worked fine.
I went back and reread my original post. When I said that I was testing my original switch and found that one was bad, I meant the light switch in the dash, not the door switches.
Thanks again.

Chris

[basketcase0302]

Chris,

Oops I believe I missed your one main question too, (what color of the original harness to feed the dome lamp circuit from your painless harness)?
Here the wire feeding the headlight switch harness-that feeds the dome lamp, (wire #54 like you stated) is a green with yellow tracer.
Hope it helps.

[DisneysPatB]

Note the two bullet connectors. These are the dome/courtesy lights wiring. [image]394[/image]

[FFRKing]

Thanks again for the replies. It’s been a few days since I have been in the shop working on the truck. This is what I get when I try to get a head start without the stuff in front of me. When I seen the pics of the bullet connectors, I remembered what I did. I removed the light switch plug from the factory harness with about 6” of each wire attached. I had to reattach the bullet connector to the black/blue wire #53 and the green/yellow wire #54 that feed the harness going to the door jamb switches. What I had forgotten was that there is a 2nd green/yellow #54 wire coming out of the switch connector that connects to the 15 amp fuse in the fuse box, which is where I connect my dome lamp feed from the EZ harness. Problem solved.
This harness really has been EZ to install. I took a lot of time to identify the wires in the steering column and ignition switch to figure out their function and connecting them has been pretty straightforward. Ignition switch is now done and next is the Dakota Digital VHX instrument cluster.

Chris

[takehikes]

Im slowly working towards adding door operated dome lamp switches. I got brackets and switches and installed them but anyone know where i can get the harness that plugs in to the switches that I can then wire in? I have it figure out how to wire it in but was curious if there was a simple plug an dplay ahrness for this.
My truck is a bone stock 68.

[FFRKing]

I used the original harness from a parts truck that I had because it was in good shape. No broken wires or crusty insulation. I did replace the sockets and door switches with a pair that I took out of a newer Ford car. Much better switch and plug.
If you can't find an original harness, using the diagram from the truck wiring manual, it is pretty simple to build.
Removing the harness from another truck that isn't already partially stripped could be quite a job. The harness you need runs along the bottom side of the dash and is held up by the dash pad studs. Getting it out means the instrument cluster, radio, and glove box just about all have to be out.
Chris