Ford F350 Dome Light Wiring Diagram
so i haven't had a dome/cargo lite for a long while -- except owhen pax side fwd door is open, then dome comes on.
not with any other door - not with the headlight sw - all the door switches have continuity w/no corrosion.
But -- I've never checked this "B-Pillar connector" -- is this the pillar behind drivers left elbow in front of left back seat?
I'm thinkin' it got wet along time ago and 3 doors + headlite sw hasn't worked since. Hints (please)???
You people will make me have wiring nightmares soon enough, lol. The fact your dome light works with one of the doors is an indicator that the black/blue wire in harness running down the driver side door sill is intact at least from the connector behind the kick panel to the left of driver's feet all the way to the dome light assembly. Do your map lights work as well? If yes the green/yellow wire in the same harness is good as well.
1) undo dash panels, remove headlights switch but leave it connected to harness, verify constant hot on its green/yellow wire. If no voltage you have a problem in the harness, likely splice S214 (EVTM says it's burried in the main harness, near the tape-out for the headlights switch, so you might as well give up trying to find it as early as now).
2) if there is voltage, turn switch know all the way to the left till it clicks and check for voltage on black pink wire - if no voltage replace headlights switch.
3) verify constant hot on green/yellow wires on door jamb switches. You may have to pull the switches out for this. Don't mess with the front passenger's switch, you already know it works. Actually how many door jamb switches do you have? My crew cab has four, and two dome/map lights assemblies, but I switched all four doors to power ones off a fully loaded '96 crew, so I'm no longer sure what was factory and what is my own add-ons. Additionally my EVTM only shows front door jamb switches, no rears. Anyways, if your front driver's switch has no constant hot then your problem is in its harness. It's powered by the same S214 splice as the headlights switch. Yes, the splice you will likely never find. So pray now you have 12V constant hot there. lol
4) with driver's door open but all other doors closed, and door jamb switch plugged in its harness, check for voltage at the black/blue wire - if no voltage replace switch. Repeat with other doors that have door jamb switches, remember to keep all doors other than the one you're working on closed.
5) pull driver side kick panel, locate connector C200 - it is black and has 6 wires on it (in 2x3 arrangement). Test green/yellow wires for constant hot both in and out of the connector (if your map lights work, skip the green/yellow wire probing, it's confirmed good). Turn headlights switch all the way to the left to the position that should turn the cargo lamp and the dome light on, then check for power on the black/pink wires both in and out of the connector. Do not waste time with black/blue wires, we already know they're good. Finally measure resistance between solid black wire again on both sides of connector, and a good ground, should be almost zero ohms.
6) remove driver's door sill cover panel, inspect harness for damage (should be none, it's quite well protected there).
7) pull interior panel off driver side B-pillar (the column between front and rear door), see if the harness heads up thru it or continues back towards rear of cab. If harness goes up look for connector C300 near the bottom of the column - it will be flat, grey in color, and have 4 wires on it. If harness goes back to rear of cab, follow it, connector C300 should then be at the base of the C-pillar (the column behind the rear door). Test wires on both sides of connector C300 the same way you did with connector C200 in step #5.
If everything so far checks out good then you got a wiring issue between connector C300 and the dome and cargo lamps.
Source: https://www.oilburners.net/threads/dome-light-question.63381/
Posted by: tybillingsley.blogspot.com