Originally Posted by spotterjoe

Watt-I got to thinking about it after I went to bed last night and thought about using diodes before I read your response. I'm going to measure the current draw of the stop light function of the marker and double the amperage of the blocking diodes. (IE if it pulls .5a use 1a diodes) It should function as follows:
connect both left & right stop light/turn signal together at the marker. Insert blocking diodes in both leads so the right doesn't affect left and vice versa. If successful, the following should occur:
1) under normal braking (no turn signals) left stop, right stop & center marker would light
2) Left turn with or without braking left turn and center marker would flash
3) Right turn with or without braking right turn and center marker would flash

This would be cheaper than the kit that you mentioned, use less parts and maintain trailer wiring integrity enabling it to connector to any standard 7 pin RV connector. I don't want to modify the 7 pin connector under any circumstances. As a last resort, if this doesn't work, just use the center marker as a tail lite as you mentioned.

I figured that you would respond as you seem to be the wiring guru. As always, thanks for your help and look forward to seeing you at SEMA 2014. BTW, when we head back to VA I'll be pulling the trailer with wife's blown 97' Mustang GT drop top (convertible) with less than 20k miles.(granny's grocery getter)

How far are you from ALB? We usually overnite there. I'll PM 'ya a couple of weeks before we leave.