I'll subscribe. I need to troubleshoot mine as well. It works with the doors, but not the switch.

 

About to go through the same process. Thanks for the info.

 

Good information. Po took out by light so I will use this info

 

I know this thread is old as hell, but I've got a quick question.

The diagram provided, as well as my original owners manual, both show that there should be a hand switch to control the cargo lamp on the driver's side B pillar.

Was this an option or standard equipment? The Owner's manual doesn't say optional, but mine surely does not have one. (79 F250 Custom)

 

I believe it is an optional equipment? You have to have the back of the cab light (cargo light) in order to get the in cab B pillar switch.

For the dome light wire, hot-at-all-times power comes goes to the headlight switch as a GREEN with YELLOW stripe wire. Dome light power comes back out as a BLACK with BLUE stripe wire. The same color scheme is used at the door jamb switches. BLACK with BLUE stripe runs out to the actual dome light. BLUE with a RED stripe is instrument panel illumination. It comes out of the headlight switch to the fuse box, leaves the fuse box again as the same color and is distributed throughout the dash.

There is no ground connection to the dome light switches or the headlight switches. These switches switch power, not ground.

1) Make sure you have 12 volts on both sides of the courtesy lamp fuse. This circuit is hot at all times, so it doesn't make a difference what position the key is in. If you have power on only one side, replace the fuse. If you don't have power on either side, then there is other work to do first.

2) Pull the dome light switches out and remove them. Make sure the terminal for the GREEN with YELLOW stripe wire in the connector has power.

3) Check the dome light switches for continuity. With the plunger all the way out (switch CLOSED), the switch should be shorted. With the plunger pushed all the way in (switch OPEN), the switch should be open. If not, replace the switch.

4) With power to the switch proven to be good, and the switches proven to be good, the dome light should light up. If the dome light does not light up, remove the cover and check for power at the dome light (not the side that's permanently grounded to sheet metal) with the door OPEN. If you have power here, yet the bulb does not light up, replace the bulb.

This will prove out the door-side; if you get to the point that the doors turn the light on but the headlight switch will not.

#7 fuse is the one to pwr the dome light

 

I have a 2010 F 150. It was a police vehicle before I bought it. When they outfitted it for police work, they disconnected the dome light. I went to reconnect the light, and found that they had cut off the electrical connector that goes to the unit. I've tried to find one like it online, but I don't know how to tell which one of many it is. It's a 3 pin female connector, and the receptacle looks squarish.

Thanx for any help.

- John

 

John welcome to FTE, just so you know you are asking a question in the 1973-1979 forum. If you ask go to the forum year for your vehicle you will probably get way better answers.

Here is the link to the 2009-2014 F150 forum.

https://www.ford-trucks.com/forums/forum193/

 

If you end up needing a new lamp assembly, the LED version from LMC is easy to install and very bright.