Here is the best description I can give. 2002 TC EX, the problem only happens when it is raining or melting snow. Something gets wet and the heater, radio, and the aux plug go dead while the van is running. I have found at if the ign key is turned to on position everything will work. Start the van and the heater, radio, and the aux plug quit. Also I have found that the wipers and the front power windows quit working. After thing dry out everything works fine. Ideas?? Thanks

 

The common answer would be a defective ignition switch, or burnt wiring at the switch connector. But....

Since this is a "Moisture -Based" concern, you will need to trace all the way out to the PDC (Power distribution Center).

Bolted to the front edge of the PDC is a Flat silver box, called a "Front" or "Forward" control module. It can also malfunction , since it cuts power to "KEY-ON" accesories during engine crank. This is done by means of a voltage signal, from.......Yep..you guessed it....The Ignition switch.

This is a quite common issue, and is a relatively simple troubleshooting task, but can very easily turn frustrating for someone not well acquainted with wire colors and locations, or without wiring diagrams.......

 

Wiring diagrams..Were can one get those diagrams..