Thank you so much for the reply; I am sorry that I neglected to respond sooner. As it turns out, the reason for this strange combination of working and non-working lights and signals was due to the fact that I had two distinct issues - my turn signal flasher was bad, and one of my rear lights is dead. I was able to fix the turn signal, so now both front signals work; however, I have encountered another road block with repairing the rear light.
To my understanding, one needs to open the van's rear door to remove the taillight fixture to access the bulb. The problem is my rear door will not open (no handle on the inside either). The handle just feels loose; it is fully manual, not electric. How would one approach troubleshooting this problem?
Again, sorry for my extremely late response. I really do appreciate the response, and any help I might receive for this question.
Thanks.