You mean the light on the instrument cluster comes on? That bulb symbol with lines in all directions is to tell you one of the light bulbs have failed. The way it works, is it senses all the current drawn by the left side bulbs with the right side bulbs (if that makes sense). If 1 bulb failed, then that side will draw less current than the other side and the failure sensor will come on. Now if you replace a bulb on one side, then in general it is better to replace the same bulb on the other side as well, using exactly the same brand and power rating bulb so that the current is the same. A 5W bulb does not consume exactly 5W of power, it depends on the manufacturing process. Even different batches of bulbs will consume different power, but if you buy 2 at the same time then usually it will be from the same batch.

With selecting gears, the only bulbs involved is the reverse lights. So my guess is that with the fender bender you had to replace 1 reverse bulb? Replace the other one as well. Or else the fender bender could have distorted the bulb housing and now your bulb (or the wiring) is making bad contact and thus drawing less current. Or the connections were exposed for a while until you got the fender fixed and water got in there and corroded the contacts.