It's possible that the knucklehead who took yours out also damaged the pickup leads.
Years back, I would've recommended that you pull the circuit from an XB-400. Weirdly, a used 400 is now generally priced at the same price-point as a USA-made 900.
If you get lucky (on eBay or Reverb), someone may have pulled a harness to upgrade.
There are alternatives that're surprisingly cheap. Here's an Amazon listing for a Belcat two-band harness --
https://www.amazon.com/Belcat-EQ-B2T-Active-Preamp-Circuit/dp/B0091CE0HM?Only $15... but notice that many of the reviews say theirs has an unbearable hiss. That
might be to the ineptitude of some home modders... or you might have to install three or more until you get a good one.
If you scroll down that page, you'll note that there are other similar harnesses, for about the same price. Here's a three-band -
https://www.amazon.com/BQLZR-Preamp-Equalizer-Harness-Control/dp/B00EQ25XLE/I've always been pleased with the tone of the XB-400, & I won't promise that a Belcat will be so good. But it'll at least move you foreward. An alternative might be to simply wire it passive.
