It turned out that the bulbs were actually bad in both her back up lights. We pulled the tail light housings and installed new bulbs. Now she can she behind her when she backs up at night. And more importantly, folks in her apartment complex can see when she is ready to back out of her parking space.
For instructions on removing the taillight housing, see: http://mikestrawbridge.com/blog/2011/04/how-to-change-taillight-bulbs-on-a-jeep-cherokee/
Labels: jeep xj tail light back up light