Wipers controlled via computer?

What computer controls the wipers in my '04 T2000? When I start the truck sometimes the wipers will sweep once without being turned on by the driver. Also sometimes the wipers won't turn on unless you restart the truck or R&R the fuse for the wiper circuit, then they return to normal operation via the knob switch. It's not blowing fuses.

I asked the last owner and he said it's a defect in the computer, but didn't specify *what* computer. Certainly isn't the ECM handling wiper functions, right? Where is the brain for this truck?

Occasionally, I will attempt to start the truck and turning the key doesn't initialize the starter. If I let the key switch return to on position, then try cranking it again, it starts, and things work correctly.

Any advice is appreciated.

VIN: 069015

 

So 2 of 3 symptoms and we have ISX ECM's. I wonder if there are other similar attributes that could help us narrow it down. Do the wipers even interface with the Engine ECM or any other computer? I thought the wiper system was just the knob, wires and wiper motor.

Sometimes when I turn the key on my check engine light is on, and there is an audible alarm, but it's not low-air or batt. Then I start the truck, the wipers sweep once, the alarm goes quiet and most times the check engine light goes off. Sometimes it doesn't go off unless I restart the truck.

Sure does sound like a computer is haywire, just need to narrow it down. I suppose I could just start blindly tearing apart the dashboard.

 

Wipers cutting out while pulling cabbage empty in a snowstorm sucks, but the whole "doesn't start when I turn the key" thing is what really troubles me. I think they are connected somehow. If the wiper phenomenon doesn't occur, the keyswitch issue does. Maybe I'll look for an "ESA" type unit in the dash and check for bad wiring or just plain worn out unit.

 

Verrrrry interesting. I found that when you have the problem where the wipers won't turn on, that you can leave the engine running and pull the blade fuse for the wiper circuit, then put it back. The wiper knob works after that. Sure sounds like a computer problem. I wonder if we have that ESA computer as mentioned above... I'll probably start digging into the dash and see if I can trace the wiper circuit.

 

My local KW dealer submitted a help ticket to their internal help desk about this problem.

Turns out there is no "ESA" type of controller in the T2000 which controls the wipers. An OEM replacement wiper switch is $355.00!!

The parts guy was REALLY helpful though and turned me onto another switch that works identically (T2000 only, not T300) and looks the same as the expensive part, but is only $65! The only difference is that the less costly one comes with the knob, too, whereas the $355 part doesn't even include a knob!

So I will go tomorrow and buy the $65 part and see if that fixes the problem. I'll post the part number here when I get it.