1993 Plymouth Voyager suddenly wont start

I have a 1993 Plymouth Voyager (not SE) 3.0L V6 with 137,000 miles. Have had no problems with it until this morning.

Without any notice my van would not start after turning off the engine to refuel. It acted as theough the battery was dead. However, I was able to turn on the radio, headlights, etc. ... all without the dome light even dimming ... so I know the battery has plenty of charge. A jump got me started and while the engine is running I am able to use the wipers, lights, etc. without the enginge dying; the alternator must be working alright.

However, when I turned the engine off it acts like the battery is dead again. And when I try to start it, I hear, and feel, a click in the center relay of the 5-relay bank mounted under the hood. Am I correct in assuming the starter relay ( center one in the bank of 5) is faulty?

Any help will be greatly appeciated! Thanks!

Rb
I'm afraid you are incorrectly assuming a lot of things. Just because your interior lights work, does not mean your battery has sufficient capacity to crank the engine. That requires much, much more current than any of the accessories do.

The jump start got the car going. That was the evidence of a dead battery.

Again, your assumption that because the radio worked and the engine didn't die, does not mean the alternator is good. You need to have these things tested to determine what is good and what isn't. 
I will have the battery tested. May I ask one more question of you: Would the battery go all at once? I started and stopped the engine several times before this happen an dhad no problems.

Again, thank you!
That's entirely possible. They can fail in any number of different ways. It could have been getting weaker for a time without you realizing it too until it just didn't have enough to start the car. 
I'll have the battery and the alternator checked.