1990 Plymouth Voyager Starting Problem & Radiator Fan

I have a 1990 Plymouth Voyager 3.3L v6. The starter cranks, but starts slow, and gets faster. If I crank for 20-30 seconds it will start. Once it starts, my rear windshield wiper turns on and check engine light appears. If I turn the car off and start again, it starts immediately with no rear wiper on, and no engine light. battery is fine. Just replaced alternator and battery. Still problems. When I jump it, it starts immediately. Have done ignition and charging diagnostics, no errors.

Also, radiator fan doesn't turn on when needed. Had to hardwire to an accessories fuse for the time being. Wires to fan seem to have no ground. When ground is added to the relay, it works fine. Traced wiring to "brain". Bad coolant sensor?