Map light LED not Lighting

[wuntrikpony]

Hey guys, I just put in a couple of LED lights for my other dome lights, but for some reason the LED bulb I got for the front map light isn't lighting up. It's the 1895 ba9s bayonet base bulb, so I know it's the correct kind. Any simple things I could have screwed up? Thanks-Dave Frank

[joatmon]

Are the LEDs polarized? (LEDs in general are, but I don't know if these auto bulb replacement ones are )Are you talking about the map light that is part of the moonroof controls? In that light fixture, there are two metal contacts for the bulb, one wraps around the base of the bulb, the other contacts the tip. In that light, the one that contacts the tip is ground, the one that wraps around the base is 12V. This seems backwards to me, I would expect the tip to be 12V and the base to be ground, but in this one it's tip=ground. Anyway, if the LEDs are polarized, then make sure that the polarity of the fixture matches the polarity of the bulb. If not, you may need to swap the two wires on the back of the moonroof control.However, if you don't have the moonroof, or if the LEDs are not polarized, or if they are polarized but the polarity matches, then it must be something else and I don't know what that would be.

[wuntrikpony]

joatmon - Thanks for the info. I believe it is polarized. Yes this is the map light that is part of the moon roof controls. The reversed polarity makes sense. I hope it doesn't require a rewire, cuz that sounds like quite a difficult task(especially if it ends up not being the issue). I just want to make sure there is no way to put the bulb in their incorrectly(because that would be an easy fix).Anyone else put an LED in the front map light on a moons/toons?

[ColonelPanic]

Sounds like joatmon hit the nail right on the head for this one. Most of the LED's I have are in fact polarized. For the dome lights and license plate lights, I had to flip the bulbs around to get them to work. For those, it wasn't an issue as they will go into the socket either way.For the map light, it will only go in one way. Put it in the socket and turn, that should be about it - not much of a chance to install it improperly. I'm guessing a standard incandescent doesn't care what is positive and what is ground - just as long as the juice from one connection on the bulb can make it to ground it's happy. But the LED does care, so that could be why it isn't working. If you don't have a multimeter, I'd be more than happy to pop out the bulb in mine and try to see which contact on the socket is positive. If we're backwards, it will require some rewiring.,

[joatmon]

For a test, can you hold the lamp so that it is in there backwards to see if it lights up? If it does, then it could be the polarity thing. You could just cut the wires and cross connect them, but it's not that hard to just pull the pins out of the connector and swap their positioins to reverse the polarity of the light fixture. Looks like a lot of steps, but it's not bad. - remove the one screw and pull off the mooroof control/maplight cover.- remove the second screw and pull the moonroof control out of the headliner.- disconnect the one connector to free up the moonroof control.- cut the zip ties or whatever else holds the wires together in a neat bundle. (I did that to mine a while ago, and can't remember what they used to bundle the wires together.)- Identify the wires that go to the light fixture. The green wire with red band is 12V, goes to the light switch. The gray wire with red band is ground, goes to the light fixture.- on the top of the connector, there is a small rectangular piece that is a seperate piece of plastic from the connector body. Use a small screwdriver to pry that piece up. It will only lift up a small amount, maybe 1/8 inch. It is a locking mechanism to hold the pins in the connector body- Using a strong needle or large pin or some such thing, reach in from the contact side of the connector, just above the contact for the gray wire, there is a thin plastic tab that holds the contact in place. Use the pin/needle/whatever to lift the tab away from the contact and pull gently on the wire from the back. When you get the tab lifted, the wire and contact should slide out easily.- Do the same for the green with red band wire. - Swap the wires, insert the gray wire in the spot the green wire came out of, insert the green wire where the gray wire used to be. You should feel the contact lock in place when you push the wire/contact into the connector- push the smal rectangular plastic pin lock thing back in on the top of the connector body.- reconnect the connector to the car wiring and test- put the control in place and replace the screw and cover.There's a blurry pic of the back of the moonroof controls at http://forums.genvibe.com/files/importe ... 8-mrsm.jpg . I'll see if my camera's macro mode can get a decent pic of the connector body and contact retainers.

[wuntrikpony]

Unfortunetly I don't have a multimeter. I would really appreciate the help! On the bad news side of things, I was trying again this morning(in better light) to switch out the bulbs, but was not only unsuccessful, but it looks like I blew a fuse somehow. None of my domes come on anymore. So it's time to figure that out first. -joatmon - Thx for the instructions. I started to take the pieces apart until I noticed the blown fuse. Will get back at that once, I get everything else squared away. -Dave Frank

[wuntrikpony]

Hah! That was it. Reversed the wires and everything is good to go. Thanx for the help!-Dave Frank