How to replace the light bulbs in the 3rd brake light ( 96+ ) 

Contributed by: Jeffrey W. Chan

Difficulty: On a scale of 1 (easiest) to 10 (hardest) this DIY is ranked 2. 

    Parts Required: 
  • 10 mm socket wrench 
  • Phillips screwdriver 
  • Soldering iron and a little bit of solder ( you will reuse most of the existing solder ) 
  • Replacement bulbs ( part # 999-631-135-90 ). Approx $3.75 each at the dealer.
Note: Steps 1-3 have been copied from Gert's DIY on How to repair 3rd tail light broken wiring
Step 1: Remove the cover of the 3rd brake light. Gently pull upwards. No tools needed. 
Step 2: Remove the 2 nuts with the use of a 10mm socket wrench 

Step 3: Remove the 3rd brake light housing. 

Step 4: Disconnect the two electrical wires. 

Step 5: Remove the two Phillips screws on the bottom, which hold the entire light assembly in place. 

Step 6: Remove the entire light stick from the car. 

Step 7: There are 4 phillips screws on the back of the light stick. Remove those screws and take off the back cover. Disconnect the two wires that hold the back plate to the circuit board. 

Step 8: Gently pry away the circuit board from the light stick housing. Start at one end and pull gently. There is nothing holding the circuit board to the housing except friction. 

Step 9: You can look at the bulbs and see which ones are blown. You can see in this picture that some blubs are darker than others. 

Here is another shot of two bulbs, the one on the left is new, the one on the right is blown.

Step 10: Using your soldering iron, remove of the old bulbs. Each bulb has two contacts that are soldered in. It works best if you heat up one side and then wiggle that side out. Heat up the other side and wiggle it out as much as you can. Eventually, the bulb will come right out. 

Note: When you are using your soldering iron, be sure that you do not create a solder bridge between the two metal rows that run lengthwise down the circuit board. This would short out something when you reinstalled everything. 

Step 11: Solder the new bulbs in place. In most cases, you can use the existing solder that is already on the back of the circuit board. Try not to heat up the solder too much, which might cause damage to the bulb. 

If you feel the bulbs are getting too hot, then solder one side, and then let that cool before doing the other side. 

After you have replaced all the bulbs, it will look like this:

Step 12: Reinstallation is pretty much the reverse of what you did to take everything apart:
  • Put the circuit board back into the housing. 
  • Reconnect the two wires from the back of the housing and reinstall the 4 phillips screws. 
  • If you have D cell battery handy, you may want to test that all the light bulbs are working correctly by putting the two wires from the light stick on opposite ends of the battery. 
  • Put the light stick back on the 3rd brake light mount, refasten the 2 phillips screws. 
  • Reconnect the two wires from the light stick to the two wires that come through the rear windshield. You may want to use a bit of foam or nylon wraps to keeps the wires tidy. 
  • Mount the entire 3rd brake light assembly on the rear windshield mounts and tighten the two 10mm bolts. 
  • Replace cover.

Here is a picture of the finished work!
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