I have an 02 MCS, and a strange problem. My left rear tail light sometimes doesn't come on. If I give it a gentle tap, it turns on. I've taken the whole assembly out, cleaned, and it still does it!
I'm hoping for a answer from someone, without replacing parts.

Any help appreciated!

 

Stupid questions, but did you check the bulb?
Sometimes the bulb's filament will break loose barely, and when you tap a light assembly the filament makes contact again to complete the circuit.
Just to be sure, you do have regular taillights that use a halogen bulb, and not any LED upgrades, correct?

 

Correct halogens...
I guess since I'm going to MINI of Loveland for their 10th Birthday celebration so I'll pick up a new one and see what happens!
Thanks!!

 

No problem. You can remove the bulb and you should be able to see the filament and look inside to see if the filament is broken. Should be pretty obvious. It is probably that issue if it turns on if you tap the assembly. A loose wire most likely would not "wiggle" if you tap the outside of the assembly if there was a loose pin on the connector.
Let me know if you get it fixed.