2011 International 4300 wiper issues

The wiper switch is actually 3 switches internally and depending one which combo of the three is how the wipers will respond. The only single wire that will make it not work is B9S, which is grey and goes to pin 7 of the wiper switch connector. The body controller is just seeing which of the 3 wiper switches has been connected to ground, which is that B9S wire. If that wire is broken somewhere, then those switches will never connect to ground and you will have no wipers. If you ground that wire, which is also the white wire of the switch pigtail, and the wipes work fine, you know that wire is open to ground. The other possibility is the actual wiper power relay control wire. The body controller controls 2 relays for wiper operation. It turns on the power relay, and also triggers a second for either low or high power. If the power relay is not triggered, you will get no wipers. The body controller supplies a ground for wire A82F which goes to relay terminal 85. If this wire is open, the relay will never trigger and wipers will never work. A82F goes to E7 of connector J4 at the body controller. It is a grey wire.

 

You are a wrath of information @Heavyd

 

The body controller must see both ignition power signal input and accessory input when the key is on ignition for the wipers to work. If one is missing, they won't work. Ignition switch input is at J3, cavity A16, wire A16, pink. Accessory is also in J3, in cavity A1, wire A12C, light blue.

 

Heavy, on the same topic, on my 4300 the wipers work only in high, and wgen turned off, will stop where they are at that moment - not return back down. Swapped switch from my oher truck, same thing. Any idea?

 

Try swapping your wiper high/low wiper relay with something else. If this relay is stuck it will cause this. Also, if your wipers are shut off and this relay clicks when unplugging or plugging it in, something is shorted between the relay and body controller. A locked up body controller could also be causing this, so to reboot it, simply disconnect battery power to the cab for a minute.

 

Real stupid question, wheres the relay? Dont see it in fuse box, thought it was just a bcm

 

I forget what year your truck is, but if you have the big fuse and relay box at the firewall outside, they are there. If your truck is newer, 07+ or so, they are in the panel in front of the passenger seat.