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So admittedly mostly for the aesthetics of the Boss302S/R/FR500S reservoir (but I also don't consider more brake fluid in the system to be a bad thing), I've picked up a junk yard 2008 reservoir to do some testing. While it was obvious I could physically plug it into the ports on my master cylinder, I was concerned with the 2 wire brake fluid level switch versus the 3 wire that came on the later reservoirs.
Anyway, after looking at a wiring diagram it appeared that the only difference was the 3 wire had an additional continuity wire that shared continuity with the 2 wire, so they could effectively be wired together with an adapter and the 2 wire sensor plugged in.
Validating my test with the stock wiring proved fruitful. I've ordered a new reservoir from Ford and will swap it in and finish my adapter cable with OE compatible connectors when it arrives.
Reservoir down/fluid "full", no dash brake light
Reservoir up/fluid empty, brake light on, low brake fluid alert on, service advancetrac on.
I cant say this is an entirely useful piece of tech knowledge but I couldn't find any real info on it anywhere so the tl;dr is, you should be able to use a larger 2008 reservoir in a 2009+ with come creative rewiring.
Anyway, after looking at a wiring diagram it appeared that the only difference was the 3 wire had an additional continuity wire that shared continuity with the 2 wire, so they could effectively be wired together with an adapter and the 2 wire sensor plugged in.
Validating my test with the stock wiring proved fruitful. I've ordered a new reservoir from Ford and will swap it in and finish my adapter cable with OE compatible connectors when it arrives.
Reservoir down/fluid "full", no dash brake light
Reservoir up/fluid empty, brake light on, low brake fluid alert on, service advancetrac on.
I cant say this is an entirely useful piece of tech knowledge but I couldn't find any real info on it anywhere so the tl;dr is, you should be able to use a larger 2008 reservoir in a 2009+ with come creative rewiring.
