what would be the most logical explanation for this. Do you think the speaker is just blown out, or has their been any cases where the wiring or headunit has short circuited.

 

Speaker, EQ, or HU.

Id start with the easiest and pull the door panel off and see if the speaker is getting signal

 

would i just use a multimeter for this, or is there an easier way

 

Another way you can go about it is to take one of your other 3 working speakers and connect it to the right passenger speaker connector. If you hear sound/music out of it, then the original speaker in that door is blown. If you don't hear anything, then it is not the speaker. But then it can be any number of things (bad right passenger channel, bad connection somewhere between the right passenger speaker connector to the amp or to the head unit, etc.)

 

dang, lets just hope its the speaker and i will have an excuse to get some nice speakers in place of the bose