Hello,
this is a quite difficult question

once I had a 3 button footswitch from Fender for my Deluxe 85, then I loan it and it didn't come back.
It cannot find schematic on the web, I've searched a lot but I didn't find schematic for this specific model.
I have found schematic for 3 button footswitch for RocPro, but is not the same.
I have found also some pics of footswitch for 185 Series (PN 028148 A) but maybe this will work... because I found a thread
here where the OP has a Deluxe 85 with a footswitch PN 028148 A instead of the original one (from Deluxe schematic we know that original footswitch PN is 0028146000).
In that thread OP says that his footswitch works and he says also something about "resistors" but maybe he is talking about diodes... because I don't see any resistor from the pic.
Does anyone have any ideas about where to find PN 0028146000 schematic ?
I attach 2 pics from the trhead about PN 028148 A, I've tried to understand schematic and trace it on the pic.
There is also a pic with original parts numbers of PN 0028146000... and it seems to me that it matches with PN 028148 A.
I'm not skilled in electronic so I cannot undurstand very well schematic, can you take a look please and tell me if the original parts number of PN 0028146000 could match with PN 028148 A pic ?