my dads mazda b3000 (ford ranger) wipers wont work, dome light wont work and key chime wont work. at first i checked all the fuses they were fine, i tryed a new wiper motor and tested the old one, they both worked fine. i also tryed a new multi function switch still nothing... anyone have any idea what could be causing the problem?

 

Bad ground maybe? A wiring diagram would help you troubleshoot.

 

bad ground or a harness came off.

 

If you can pull the radio there is a module right behind it that controls all those functions (GEM/CTM) I would check those connections, maybe start wiggling wires and connectors all over and see if anything happens. Module failure is rare but possible. Think about anything that might have happened or been worked on latelythat could relate to the problem. Also is a dumb question but you did check the fuses under the hood too right?

Elec problems don't really bother me much, but they can be a PITA to find/repair. I suggest getting a manual with electrical diagrams for help.