Interior: How to install a dome light on a vehicle with a sunroof
07-24-2008, 02:30 PM
#1
Senior Member
Thread Starter
How to install a dome light on a vehicle with a sunroof
Alright, most people who own a Cobalt (or G5) with a sunroof have at one point or another cursed the fact that these vehicles do not have an interior dome light, instead having only the small map lights in the rear view mirror. In this guide, I'll show you how to install a factory dome light in a vehicle that has a sunroof and have it look like it was always there.
What you'll need:
1 Dome Light Housing Part#22736100
1 Dome Light Lens Assembly Part#22736098
2 Bolts with nuts and lock washers (I used 1/4" bolts 3/4" in length)
10 1/4" rubber washers
3 Quick wire taps
Some wire
Wire strippers
Soldering iron & solder
Sharp Instrument For Cutting
Drill
Writing Utensil
Electrical Tape
Anything else you think you may need to complete this
Step 1:
Since you're dealing with electricity, probably wise to disconnect the battery. No major risk here, but you never know. After that, remove the rubber trim from around the sunroof.
Step 2:
Pull the headliner down a bit and take a look at this large metal brace with two holes in it. This is what the dome light will eventually be mounted to.
Step 3:
Pull the headliner down a bit where the sunroof switch is located and find the wire harness that leads to the rear view mirror. There are three wires in this, Black, Gray, and Blue.
Step 4:
Follow this wire harness as the wires join up with the rest of the wires up in there and follow it around the sunroof's left side. You will be tapping into these wires to make your dome light work. You can tap into them anywhere along their length, I just used the left side of the sunroof because it's the easiest way to access them.
Step 5:
Prepare your dome light parts. On the left is the housing, on the right is the lens assembly.
Step 6:
Grab the wire you will be using and strip one end of each. If you have the same colors of wire it will greatly reduce confusion, black, gray, and blue. Solder the blue wire to the rightmost terminal in the dome light housing. This has what looks like a small fork sticking up through it. Solder the black wire to the other terminal with the fork thingy, which is the leftmost terminal. The gray wire must be connected to the terminal beside the black wire, either on top or in the location where the plug would normally go. I chose to solder mine where the plug goes so that I kept all the solder locations away from each other, also helps give you more maneuvering room. There are four pins in the plug area, the gray wire goes on the second from the left if you're viewing the housing from the top (light bulb) side.
Step 7:
Mark the location of the holes in the metal brace onto the housing. The holes are roughly 5.5cm apart, which correspond to the spots just outside the little plastic "dividers" in the housing. Drill two holes in the housing to match these holes in the brace.
Step 8:
Do the same for the headliner, mark the holes so you know where they are.
Step 9:
Hold the housing up to the headliner, matching up the holes. Trace a rough outline of the main area of the housing.
Step 10:
Cut out the hole.
Step 11:
This step is optional, but highly recommended. Take the housing and turn it over. Cover up the area with wires with electrical tape or other covering of your choice. The idea here is to eliminate the chances of a short circuit forming and you blowing fuses.
Step 12:
Connect the wires from the housing to the wires running along the side of the sunroof. I used the quick taps for simplicity, feel free to use whatever you're comfortable with.
Step 13 (updated):
Place a rubber washer on each bolt, then feed your bolts through the holes in the metal brace. Once through, place two more rubber washers on each bolt, then feed the bolts through the housing. Place two more rubber washers on each bolt and secure everything using lock washers and nuts. If your bolts are too long the switch in the dome light won't operate as it should, so test it out now to see if it slides all the way in both directions. I added rubber washers to this step because it virtually eliminates the chances of a short developing and blowing the interior light fuse.
Step 14:
The lens assembly locks onto the housing using four tabs. Make sure the headliner isn't in the way. If it is, cut more of it off until everything is clear. Once done, take the lens assembly and push it onto the housing. You will very likely have to push down from the top in order to do this, as it's quite a tight fit. You'll hear (and feel) a click when the tabs interlock. Once all four tabs are locked in, you're finished. Clean up the mess you made cutting apart the headliner, reconnect the battery, replace the trim around the sunroof, and try your new dome light out. You'll appreciate it more once it gets dark.
Congratulations, you just made the interior a lot brighter. One small thing to take not of. I installed my dome light with the large light facing forward, and the two smaller lights facing back. You may choose to install it the other way. It's all a matter of personal preference. Enjoy!
UPDATE: I've installed LED bulbs in both the mirror lights and the dome light, so I figured I'd try to show the difference between having the dome light installed and the stock way.
Here's the LEDs during the day:
Now at night. I've retaken these photos with the car parked in my garage with all the lights off. This is the absolute best way to show the difference in illumination in photos that I can come up with, so I hope they get the point across.
This is just the map lights on the rear view mirror lit:
This is the mirror lights plus the main (or front half) of the dome light:
This is the mirror lights, the main dome light, as well as the map lights on the rear half of the dome light:
Hope that shows how GM screwed everybody that got a sunroof by not putting the dome light in from the start.
What you'll need:
1 Dome Light Housing Part#22736100
1 Dome Light Lens Assembly Part#22736098
2 Bolts with nuts and lock washers (I used 1/4" bolts 3/4" in length)
10 1/4" rubber washers
3 Quick wire taps
Some wire
Wire strippers
Soldering iron & solder
Sharp Instrument For Cutting
Drill
Writing Utensil
Electrical Tape
Anything else you think you may need to complete this
Step 1:
Since you're dealing with electricity, probably wise to disconnect the battery. No major risk here, but you never know. After that, remove the rubber trim from around the sunroof.
Step 2:
Pull the headliner down a bit and take a look at this large metal brace with two holes in it. This is what the dome light will eventually be mounted to.
Step 3:
Pull the headliner down a bit where the sunroof switch is located and find the wire harness that leads to the rear view mirror. There are three wires in this, Black, Gray, and Blue.
Step 4:
Follow this wire harness as the wires join up with the rest of the wires up in there and follow it around the sunroof's left side. You will be tapping into these wires to make your dome light work. You can tap into them anywhere along their length, I just used the left side of the sunroof because it's the easiest way to access them.
Step 5:
Prepare your dome light parts. On the left is the housing, on the right is the lens assembly.
Step 6:
Grab the wire you will be using and strip one end of each. If you have the same colors of wire it will greatly reduce confusion, black, gray, and blue. Solder the blue wire to the rightmost terminal in the dome light housing. This has what looks like a small fork sticking up through it. Solder the black wire to the other terminal with the fork thingy, which is the leftmost terminal. The gray wire must be connected to the terminal beside the black wire, either on top or in the location where the plug would normally go. I chose to solder mine where the plug goes so that I kept all the solder locations away from each other, also helps give you more maneuvering room. There are four pins in the plug area, the gray wire goes on the second from the left if you're viewing the housing from the top (light bulb) side.
Step 7:
Mark the location of the holes in the metal brace onto the housing. The holes are roughly 5.5cm apart, which correspond to the spots just outside the little plastic "dividers" in the housing. Drill two holes in the housing to match these holes in the brace.
Step 8:
Do the same for the headliner, mark the holes so you know where they are.
Step 9:
Hold the housing up to the headliner, matching up the holes. Trace a rough outline of the main area of the housing.
Step 10:
Cut out the hole.
Step 11:
This step is optional, but highly recommended. Take the housing and turn it over. Cover up the area with wires with electrical tape or other covering of your choice. The idea here is to eliminate the chances of a short circuit forming and you blowing fuses.
Step 12:
Connect the wires from the housing to the wires running along the side of the sunroof. I used the quick taps for simplicity, feel free to use whatever you're comfortable with.
Step 13 (updated):
Place a rubber washer on each bolt, then feed your bolts through the holes in the metal brace. Once through, place two more rubber washers on each bolt, then feed the bolts through the housing. Place two more rubber washers on each bolt and secure everything using lock washers and nuts. If your bolts are too long the switch in the dome light won't operate as it should, so test it out now to see if it slides all the way in both directions. I added rubber washers to this step because it virtually eliminates the chances of a short developing and blowing the interior light fuse.
Step 14:
The lens assembly locks onto the housing using four tabs. Make sure the headliner isn't in the way. If it is, cut more of it off until everything is clear. Once done, take the lens assembly and push it onto the housing. You will very likely have to push down from the top in order to do this, as it's quite a tight fit. You'll hear (and feel) a click when the tabs interlock. Once all four tabs are locked in, you're finished. Clean up the mess you made cutting apart the headliner, reconnect the battery, replace the trim around the sunroof, and try your new dome light out. You'll appreciate it more once it gets dark.
Congratulations, you just made the interior a lot brighter. One small thing to take not of. I installed my dome light with the large light facing forward, and the two smaller lights facing back. You may choose to install it the other way. It's all a matter of personal preference. Enjoy!
UPDATE: I've installed LED bulbs in both the mirror lights and the dome light, so I figured I'd try to show the difference between having the dome light installed and the stock way.
Here's the LEDs during the day:
Now at night. I've retaken these photos with the car parked in my garage with all the lights off. This is the absolute best way to show the difference in illumination in photos that I can come up with, so I hope they get the point across.
This is just the map lights on the rear view mirror lit:
This is the mirror lights plus the main (or front half) of the dome light:
This is the mirror lights, the main dome light, as well as the map lights on the rear half of the dome light:
Hope that shows how GM screwed everybody that got a sunroof by not putting the dome light in from the start.
Last edited by NCC-2000; 04-29-2009 at 09:26 PM.
07-29-2008, 08:15 AM
#5
Senior Member
Thread Starter
That's easy, find out what part of the thing is rattling then install something to stop it. I don't have any rattle issues with mine, but then again I only have the stock sound system so I'd have to really crank it to get anything to rattle and by that time I'd have a wicked headache.
07-29-2008, 09:49 AM
#7
Senior Member
Thread Starter
The sunroof is large enough that it eliminates the section of the roof where the light normally goes, so I guess they just figured it was easier this way. Lazy designers is what I think. They didn't want to bother thinking of moving the light back a few inches instead of completely removing it, but I guess I just proved them wrong lol.
07-30-2008, 06:55 PM
#10
Senior Member
Thread Starter
Any kind of automotive wire will suffice. I had an old engine wiring harness sitting around so I ended up stealing some wire off that, but really any wire will work as long as it's not too thin.
08-09-2008, 08:45 AM
#13
Senior Member
Thread Starter
It's not as bad as you might think. I had the same worries when it came time to cut out the hole. I thought to myself "if I screw this part up this will look like ****" but really if you measure everything out properly there won't be any problems. Get something that's nice and sharp though, the headliner's got a lot of material to slice through.
08-09-2008, 02:35 PM
#14
Premium Member
Wow what a great write up, I too was wondering why GM didnt give us that damn lamp assy. This is something that I am definately going to do. I take it you got the lamp from a GM dealer correct?
08-09-2008, 02:42 PM
#16
Senior Member
Thread Starter
You can order the parts from any place that sells GM parts directly, be it a dealer, web site, etc.
08-09-2008, 02:50 PM
#17
Premium Member
08-19-2008, 11:28 AM
#24
Senior Member
Thread Starter
Keep the sunroof shade closed when cutting into the headliner if you're worried about damaging it. I used one of my utility knives from work, but like I said, any sharp thing will work, as long as it's sharp. I had to put a bit of force into it to cut through the hard layer of the headliner.
