How to repair cracked vinyl driver's door armrest on a 2000 Grand Cherokee Laredo?

I had the same problem with my 98 Gr Cherokee and I repaired it with a vinyl repair kit (about $8) I purchased at Wal-Mart. You just cut out the cracked area, so you have a straight edges aroud the area. Then mix the colors to match your problem area and spread it over the hole. Then take the textured patch (included in the kit-it gives the repair area that textured look) place it over the patch and rub over it with a hot metal disc (also included in the kit-and heat it with an iron). It was pretty east to do and it is hardly noticable. You may want to test out a very small spot with the vinyl repair kit. I used a kit from an auto parts store on my '99 Grand Cherokee. I followed the instructions to the letter. I replaced a 2 inch by 3 inch area and matched the camel (tan) color perfectly. After a few weeks of sitting in the sun, the patch changed from camel to light green. Different folks have different results, so it's best to test in a small place and give the patch a chance to age a bit before committing to a large repair.