Ballast is bad. Lowes doesn't sell them anymore. We got a big long thread on it, but you might find some still on their clearance table.
Other options:
1) They sell the ballast for $6.99 at Home Depot. You can grab a new light bulb while you're there.
2) You can go back to Lowe's and buy an all-in-one "under shelf" flourescent light fixture for about $8.99 that has the ballast and bulb built in. Then you'd remove your original light fixture, mount the new one, and wire the plug into the cab's marquee power wiring...