There are a couple of relays responsible for more than one function, in the driver's footwell, right side up half under the dash. Accessory Relay and Battery Saver Relay.
Those were what I first suspected. However other things like the wipers and defroster, do not appear to use these relays. Because it would seem just a little too coincidental for multiple different things to fail at once, the one central thing that might affect all of them is the GEM failing, but the GEM is far more expensive than fuses, relays, a wire short or break that needs soldered so I would explore the less expensive things first.
If your time is more valuable than the cost of a GEM then you could get the part # off your GEM, find a junkyard with near if not same year of vehicle and see if they have a GEM with that part #. If they have a good return policy so you can try it and return it right there in their parking lot for a refund if that's not the problem, then it could be the easiest attempt at a solution if all these factors work in your favor.
You have too many things failed at once for a single forum topic if it's not the GEM. If you have a multimeter and familiarity using one, you could pick ONE of those non-functional circuits, check out the wiring diagram for that respective circuit. You can download them all following the link below in my sig, and get some idea what measurements should be if it's something other than the GEM affecting everything.
If you pick one and start tracing it with a multimeter, I can give some assistance on how to figure out where something is going wrong. For example on any of those if it runs through a fuse and the fuse is good, so it's getting power to the respective relay for it, but the relay is not conducting to the functional part because the GEM isn't grounding the relay coil, then you'd have a GEM problem.
If on the other hand power isn't getting to the relay, either the main supply contact or the coil power contact, then you have a problem before the GEM has a chance to ground the relay coil to energize it.
If the problem is the GEM not grounding the relay coil, you can run a jumper wire from the relay coil ground pin to a chassis ground and see if that completes the circuit and allows the problem function to start working. It is harder to try to talk about this in general than to narrowly focus on one function and follow through on that circuit.
Oh, there is one other thing to try. There are a couple big connectors under the hood that connect a lot of different circuits together, you might unplug, inspect, clean if needed, and plug them back in. However many of those are exterior sensors and such, not as much things like the dome light as far as I know.
2nd gen issues? Try this first!
It's also possible that it's late and I overlooked something. I mean that I wouldn't rush to a junkyard and buy a GEM just yet, but at the moment that's my best guess based on the info presented.
