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Adding lighting to H3 rear window switches

JPaul

Well-Known Member
Messages
2,400
Location
Way up north, UT
So I wanted to replace the bulbs in my H3's window switches with LED's since they were starting to burn out. I knew that at one point the rear window switches had working lighting (which based on the schematics was only during the 2007 model year) so I thought I'd try to get them working again in my 2008.

Turns out GM removed the wire from both the body harness as well as the door harnesses, so unless you really want it to work like it was designed and tear apart the entire interior to add the wire to the harness (Which is possible by the way, I figured out how to source the contacts for the various plugs so you can just crimp a new wire and pop them into the existing plugs) you're only other option is to modify the switch itself to provide power to the light via an existing power source.

I chose the easier route of modifying the switches, and the power source I chose to use was the one coming from the driver door switch via the passenger window lockout. This way when the lockout is disengaged (your passengers can control their own windows) the light will illuminate, and if you engage the lockout (preventing the passengers from controlling their windows) the light will turn off. This only applies to the rear window switches since the front passenger switch does still have lighting wired in for all model years of the H3, though if you wanted the same functionality on the front passenger switch you could make it work.

So here's the process I went through:

First, pop both switches out of the doors using a flathead screwdriver or some other prying tool. They just clip in on both ends so it doesn't matter which end you work from, unlike the front doors that have only one clip and a hook on the other end.

Then pry off the trim piece, and then you can pry apart the switch housing (it just hooks together with four clips).

Inside will be the circuit board, the rubber seal, and the light pipe that carries light from the bulb to the switch toggle.

Here's a pic of the switch circuit board, what you'll be doing is soldering a jumper between tow of the pins of the connector. The pins are conveniently right across from each other.

CZYBvV0.jpg


Simply solder a wire between the two pins as shown below, and that is all you need to do to modify the circuit board:

eu8Lzsp.jpg


Now when the vehicle is on and the lockout disengaged, the rear window switch lights will illuminate. If you're using regular incandescent bulbs that's all you need to do and you can simply reassemble everything and install it back in the car. If you're using LED replacements like me you'll have a couple options, I chose the harder one of course.

Here are the LED's I used: https://www.amazon.com/gp/product/B018LUL8BA
 
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JPaul

Well-Known Member
Messages
2,400
Location
Way up north, UT
So with LED's you have two options, either modify the existing bulb bases to use LED instead of the incandescent bulbs, or simply solder LED's to the circuit board. Honestly the second option is the better one due to the fact that depending on the type of LED you're using you might have to make additional modifications when trying to reuse the bulb housing. The reason for this is that the type I used shines straight up, which works fine on the front window switches but on the rears it barely will illuminate the switch toggle because of the layout of the light pipe. The LED really needs to be able to shine to the side to point at the light tube. If you solder the LED in place you can simply point it directly at the light tube and have great illumination. Otherwise read on to find what you need to do to modify the bulb base.

Here is the start of modifying the existing bulb (this needs to be done for the front passenger side as well since it uses the same bulb base, the regular T4 New Wedge bulbs will NOT work since the contacts on the circuit board are on the other side of the board).

You have to use a very thin and small flat head screwdriver to first bend up the bottom contact so that you can press out the contacts. Use the screwdriver to wedge between the top contact and the housing to start pushing the contact out through the bottom, then grab it with some fine pliers and finish pulling it out. Do the same for the other side. The you can bend the bulb's wires out and pull out the bulb.

2ruORCZ.jpg


Dissembling the LED bulb is much easier, just straighten the wires and pull it apart:

O26fL2A.jpg


Insert the LED into the old base, trim the wires to about 1/4" left, and bend the wires in place and carefully insert the contacts.

zOfr2Ew.jpg


C0P7Esb.jpg


2JqynOU.jpg


QoxjNWu.jpg


You'll want to install the bulb into the circuit board next, because you're going to need to file away at the LED body to get light to shine out the side. Use a 9v battery to figure out which side is positive and which is negative and mark negative with a black marker. Next install the bulb in the board with the negative side to the large sheet of copper and the positive to the thin copper trace.

You'll next want to take a small file and very carefully file away the portion of the LED housing that is facing towards the pin you soldered the jumper to earlier. This will be pointing at the entrance to the light pipe and help a great deal with illumination. If you simply soldering the LED to the circuit board (can you see now why I said that's the easier option?) then this is the direction you'll want the LED facing.

File away just enough of the white plastic to start revealing the clear plastic from the side. It's probably hard to see in the pictures. Be very, very careful not to file too far in or down because that could destroy the LED.

cbpmIIK.jpg


Picture taken facing the side I filed:

YqWyyLN.jpg


Picture of the opposite side, you can tell the massive difference in how much light is visible from the two sides (Yes the LED is still lit):

mEmUW0x.jpg
 

JPaul

Well-Known Member
Messages
2,400
Location
Way up north, UT
Now the next thing to do (first thing I tried really before I decided to file the LED) is add a reflector to help guide the light being shone straight up to off to the side.

I simply used some tin foil that I super glued to the light pipe and shaped a little bit. It definitely helps, but again, just solder the LED's to the board and save yourself a ton of time and headache.

PIoWBw0.jpg


jmIq8RI.jpg
 

JPaul

Well-Known Member
Messages
2,400
Location
Way up north, UT
Here is the finished result:

Driver door (dead simple, just replace the bulbs):

WTYPL3Y.jpg


Front passenger door (use the base from the old bulb or just take apart the switch and solder the bulb to the board):

T3fqvKw.jpg


Rear passenger door (Just solder the dang LED to the board will you??):

nhEIG13.jpg
 

alrock

El Diablo
Staff member
Messages
10,426
Location
Scottsdale
Nice job! It was easier for me to buy an '07. Thanks for the great write up, I'm sure it will help others.
 

Teahead

Well-Known Member
Messages
66
Location
Tacoma
it appears starting in 2009, rear switches has NO PROVISIONS for a light bulb whatsoever
 

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Exodus

Well-Known Member
Messages
82
Location
Alaska\Philippines
well krap !! i have an 08 also and thought th bulbs were strangely burnt , guess not :( no biggie im in Alaska and half the year i dont need lighting
 
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