QuestionI read your response to Rick concerning his 2004 Pacifica. I basically had the same issue. Took it to my garage where the wiper motor and fuse box were replaced. Problem solved until 3 months later. Driving last night turned the wipers on and lost all lights, and accessories. Car off lights work. Car on would not. Had to finish the drive with the hazards on. The only other thing that happened with my car is it actually affected the tranny I believe the car would seem to shift down into low gear and stay there. Did that again last night?
AnswerHi Jim,
Besides the headlamps what were the other 'accessories' that didn't work?
By the tern "fuse box" do you mean the Integrated power module (which is where all the fuses are? It is much more that a fuse box, and I wonder if that has failed again? You might want to go back to the garage because it either has failed or it wasn't repaired properly the first time.
The cause of this is not obvious. The wipers and headlamps are on separate switches but they do both communicate to the body control module as regarding their switch positions. Then the body control module communicates via a digital signal to the Integrated power module which powers the lights and the wipers and virtually everything else. Somehow, the signals are getting crossed up. The lights and the wirpers don't share power circuitry in the Ipm except that there is a 'run relay' which powers many fuses including both the headlamps, the wipers, and many other circuits. I don't see how the wipers would run and not all the other items on the that 'run' relay. So it could be the wiring from one of the lamp or wiper switches to the bcm, the bcm, the wire from the bcm to the ipm, or the ipm itself is at fault.
My thought is that there may be a fault code that the body control has stored in its memory which will tell us where to look for the cause of the problem. You generally need to get that memory access via a plug in code reader that goes into a socket under the dash. You would be looking for 4-digit numbers preceded by a B.
Just on a chance try turning the ignition switch "on-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time. Then watch the odometer window of the cluster to see if the mileage reading changes to show any 4 digit numbers. Usually only engine codes (P prefix) are shown this way, but maybe a B code will appear. If not then go to a nationwide auto parts store where they might do a free readout, or to an independent shop where they will charge $40 or less to do a readout with a more sophisticated reader that can access the B codes.
Let me know what codes you get, and maybe your "garage" can try to get the code.
Something is clearly going on here that wasn't fixed the first time around.
Roland
