Reverse lights not working

I saw 2.4L in Voyager didn't see that engine in Grand Voyager? Did you check that fuse, upper left, in diagram? Not only check the fuse, use a test light and check voltage at fuse, the fuse circuit goes hot with key on. As you can see white wire carries voltage to switches, hot all the time, if fuse is okay, you can use test light to check. The wire from the switch, violet with black tracer carries voltage to reverse lamps. Check for voltage. If the other rear lamps work, don't think ground is the problem.

If you have voltage to and from switch on the proper wire colors, it isn't the fuse. My information says fuse 12--10 amp. I don't have very good picture of fuse box? Maybe you fuse box or fuse box cover has a legend on it, that will tell you which fuse is which?

Can you pull reverse bulb? Use test light in bulb socket, voltage and ground, does the test light come on? Of course, key on, trans-axle in reverse.
Does the diagram I posted match what you have exactly? I'm talking about wire colors.

Let us know what you find?

Did you try pressing in on the bulb with it in the socket. Sometimes the bulbs don't make good contact. If I'm thinking correctly, the center of bulb socket is voltage and the wall of bulb socket is ground. If I understand your last post, it looks good.

I see, so the test light came on when connected from center to side wall?

So something wrong with bulb socket? The emery cloth might not have been a good idea? The bottom black wire in diagram is ground, did you check that.

Maybe a problem with bulb socket. Sometimes if I think bulb isn't making good contact, I would put a blob of grease on the bottom button to help it make contact. You can try it. The out side metal part of bulb you could try a little tin foil to make better contact. This is just for testing, if it lights up, the bulb isn't making good contact with socket.

I'd have to try different bulb socket or bulb? If I think of something else, I'll let you know.