The light in the automatic gear shift console in my 2006 Matrix is out. I checked the fuses and they are fine. could the bulb need replacing? How do you get to the buld to replace it?

Within the gear shifter cover, remove the cover and replace the bulb!

fuses blow because of dead shorts or excess current draw
to blow a 15 amp fuse indicates a dead short
by disconnecting the rear lights , the problem is in something else you have replaced
could be a problem in the head light wiring

There is no fuse specific to this light. This light is fused with the park lights. If the park lights work,suspect the shifter bulb to be burned out

Most console bulbs are 194. Napa or any parts store.

The "back-up Reverse light switch I believe is incorporated in the gear shift selector Dash or console mounted?

all you have to do is pop the little square piece around the gear shift lever up and there is a wire with a tiny bulb on it. It is a pain in the butt to get all the pieces back in place and put the square piece back down. i have had to replace mine like every 6 months. be careful not to use too much force because you can break the clips that secure it in place and that will look worse than your bulb not working

1. Lift the little carpet in the console rear to the automatic gear shift. Pry with a small flat screwdriver will do the job.2. Remove the three Philips head screws.3. Remove one Philips head screws on each side of the rear console, they are located at the bottom front of the rear console panel. You may have to move the driver and passenger seat back to see the screws.4. Grab the back of the rear console and gently wiggle, pull backward and lift upward. Pull the hand brake so it is easier to remove the loosened rear console panel. 5. Use a flat head screwdriver to pry the rectangular 'cushion' around the automatic gear shift. Gently pry at various spot and the rectangular 'cushion' will come off easily.6. Now you are just one more plastic cover away from the burned bulb. The plastic cover that has those 'P'ark, 'R'everse, 'D'rive letters is held in place by four snap on latches. Use a small flat head screwdriver and gently push the black latches inward in a downward motion, once the screwdriver head gets inside the grey latch holder it will free the black latch. Work on each of the four latches in turn.7. Wiggle the plastic cover until it is completely loosened from the four latches. Gently lift the plastic cover up. The automatic gear shift will stop the plastic from being lifted out completely. You still have enough room to work with. You will see the little burned bulb directly below those 'P'ark, 'R'everse, 'D'rive letters. Gently pull the bulb out. I got my replacement bulb at Canadian Tire, Motomaster instrument replacement bulb 194LL (clear, long lasting, 2 bulbs for $2.99Cdn). It is a push-on bulb.8. Test the bulb by starting your car and dash lights.9. Snap back the plastic 'P'ark, 'D'rive cover. Put back the rear console panel and finally the rectangular 'cushion' around the automatic gear shift.

That is a very tough bulb to replace. Once you get the center console pieces out of the way there should be a couple of screws or blots that hold down the trim around the gear shift. Remove those and lift gentley. You will barley be able to access the bulb. but it can be done.

did your dash board light when you turn on the park light, that mean the fused is good , there is a small bulb in there ( gare shift control)
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If the shift console is on floor then look for bolts holding it down.  Take out bolts and then you can maneuver console so you can see where light is plugged in and get the right light to replace it.  It will probably be a small light which tend to cost a bit more, but at least you'll have the light back.