Hi guys, i have a 94 f150 scab 4.9 I6

i went to the junkyard to pick up a couple of map lights to replace my dome light with and found two great simple lights from two different dodge caravans. anyway, long story short. when im done connecting . . . nothing happens. no map lights with the switches and no dome light constant. nothing. now, im assuming at this point that its bad bulbs . . . 3-two that came with the map lights and coincidentally totally not because im doing something wrong, the original dome light bulb lol.

the first map light piece that i used has a harness with three wires coming out of it. i figured, ok its a ground. i just connect the other two to the two coming out of the dome. well turns out only one black wire was going into the dome and the green wire was just held in place by a clip to the cab roof. after wondering why the hell this was there seemingly serving no purpose i took out my haynes and deducted that that is a wire placed there a. for the map lights the truck came with already(mine didnt) or b. for the map lights you wanted to install later(my case)

so fine, all i have to do is take those two wires and connect them to the two wires i decided were not grounds and voila right? wrong

that didnt work. ill spare you the details about how i ended up cutting the harness off and tried every combination of splicing wires together to get it to work and go straight to . . .

i got the other map light piece and noticed it only had two wires coming out of the harness. im like . . "sweet!" . . . not exactly lol. it still didnt work.

i tried switching polarity, i tried only one wire like originally found in the dome setup, i tried . . . well anyway, i think the bulbs are bad. i tested the wires and they read .13 while on(key set to start and light switch on) and something like .32 while off.

any ideas? thanks guys. hopefully its just one of those weird "what are the odds?" things and its the bulbs in which case im glad i didnt end up going to the casino like i planned lol

 

First off, there are a couple of different configurations for domelights. Some manufacturers run a hot all the time wire to the bulbs, and then run another wire away from the bulb to the door switches. The door switch grounds the wire, and that makes the domelight come on. A lot of older vehicles use this set-up. You can tell if the socket you have is setup for this, since the bulb socket will not be grounded.

As far as the maplights, you need a constant hot wire up there to make them work. Do you have a wire up there that has 12 volts on it all the time? I believe your Ford does not use the grounded wire system, so your original socket will be grounded. But you will only have 12 volts up there if one of the doors is open. So if you hook your maplights to this, they will only work with the door open.

 

well like i said, there is another wire up there(green/yellow) that i imagine is for some sort of upgrade or map lights cause it was just sitting there before. the power wire for the dome light was not grounded no. so the other one must be for map lights. what i need to do first is replace the bulbs and make sure its not just that.

 

What I would do is get a testlight or voltmeter, and see what wires have power and which ones may not up in the cab.

I would also get a small battery charger and take the fixtures you have and see what combo of wires makes what work.