Sidemarkers stop working, but tap and they're fine
 

I have this a lot on my car and it seems less than Porsche-like. I'll get the warning telling me it's out, I get out of the car and tap it and it goes back on. I've had it on both of my sidemarkers and they are original. What's the deal? Needs to be rewired or what?

moisture may have seeped in creating poor contact. It should take less than 5 minutes to check them. I'd clean the contacts and/or change the bulbs and check the o-ring seal. Most likely that will solve your problem.

I agree. Just pull them out and have a look. It's most likely to be a loose or corroded connection between the bulb and the socket since it comes back on when you tap it.

Pull the rear of the side marker out away from the car and they will just pop out. The metal bracket will have to be bent back to snap them back in.

First remove vinyl plug from wheel well, it's right inside from the rear of marker light.Put a small screwdriver in the hole and press the release tab inwards before pulling side marker light out.

Happenned to me. I replaced the bulbs and the problem went away. must have been a loose bulb filament.