Ok here's the deal, I picked an early 90's f250 dome light with the separate map light. I was looking to upgrade my Comet and since the headliner was out for paint why not upgrade. My factory dome light never worked, I replaced the bulb and still no dice. The wiring (blue w/black tracer) looked fine and hasn't been tampered with. I replaced the 3 pin door jamb switch and still nothing. I am getting 12v at the blue wire with the dame light on. 12v is inconsistent at times and drops. I noticed the door buzzer on and flickering off matching a drop in voltage with the buzzer disengaging. I replaced the headlight switch and still nothing. I'm trying to get the factory dome light working before I switch to the new light. Anybody have any suggestions.
It's appears to be grounded to the body. There's a metal bracket the light is attached to, that bracket attaches to the body (slips on). I sanded a section so it should be a good ground.
If operation is OK from dash, problem is likely the connector on door switch... This would also account for the intermittent buzzer operation... Power should be fed to door switch on the green & yellow wire, when switch is closed(door open), power is fed to black/blue wire... For the map light to operate as intended, you'll need to tap into the green/yellow wire and run a feed to it's switch in dome light...
1. Unplug the buzzer and see if voltage drop continues. It may be defective. 2. Check the voltage for the blue/black wire where it plugs into the harness. 3. Check the continuity of the blue/black wire. It may have gotten stretched or has a bad connection with its plug. Micah Just saw Comet posting at the same time along the same thought.
I'm finding an issue when the dome light bracket is grounded to the body. It creates a short and I no longer get any current to the black/blue or green/yellow. The factory light worked for a minute then went off, I did however hear the door buzzer buzz when the light was on.
Assuming you're talking about the orig dome light, unless there is a defect in the socket, there is no such thing as short on ground... Ground is a short... You have a high resistance connection in the wiring somewhere, if you are using a Volt Meter put it away and use a test light instead... Check for power on either side of door switch(black/blue and the green/yellow wires)
So, after a ton of choice words, a new headlight switch and a new door jamb switch I found out the plastic door jamb switch button was not going back to it normal position and not allowing the light to come on because it was barely on the off position. The new jamb switch (standard brand) is all plastic. I think I'm going to buy an nos one on eBay. Thanks for the quick responses. Did I mention I hate wiring, not because I suck at it but it drives me crazy.
Luckily I like wiring... Sometimes I'm not very good at explaining to someone else but yet to find something I can't fix... Currently I'm working on a 1937 Rockola juke box tube amplifier(no I don't have the box), probably bring it back to life later this week...
Schematic?? What schematic?? I couldn't find one, so I drew my own(less the power supply transformer)... There is one online for the '36 model but much of the circuitry is different from mine, plus it's had a second amp stage added probably early '50s so a magnetic cartridge could be used... http://s14.postimg.org/gjdqj6mpt/6_B5ampfinal.png
Squiggly line, squiggly line, circle , squiggly line circle, ground.... That's what the attachment looks like to me.
