You may want to look at some of your backboard transistors. I had an entire bank of flashers on a T3 die. After spending the majority of my time checking bulbs, wiring, continuity, it wasn't until I snapped a pic of my backboard to noticed that one of my transistors was discolored and barely cracked. Turned out to be the culprit.
According to the manual, the super charger flashers go back to transistor Q40 on the backboard. Locate that and do some testing. Transistors are not too difficult to replace. The part is cheap(just a regular TP-102, I believe). Only recommendation is that if you do replace it, snip the legs off as opposed to trying to desolder all three legs.
General Region of Q40(you will have to remove your speaker panel to get a clear view of it)
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Q40 on the board
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