If you were working on the speedometer, something could have loosened from the connector on the interior side. You mentioned fuses; does your car have an under-hood fuse box? If so, this should be where you find the fuel pump relay, which should be the same as the other relays, if you want to swap. But given everything else that's won't work (radio, turn signals, wipers), I doubt that's the problem. Someone here might try to find you a wiring diagram so you can diagnose where you're not getting current.
You already mentioned the PCM. When I had a problem with the one on my Dakota, it was the connector that sometimes loosened, not the PCM itself, and when it did, several items wouldn't work. The metal part where the screw inserted came loose, and I had to JB Weld it back in. And the plastic snap on one side broke, so I occasionally had to push that side in.