For the last week or so my rear wiper makes one pass across the window every time I turn the car on. At first I thought I had accidentally turned the wiper on but it's become apparent that's not the case. I tried actuating the wiper with the switch once the car is on and it acts normal at that point. Wipes when it's on and doesn't when it's off. It also sprays water like it should. Anyone have any ideas why it would make 1 pass every time I turn the car on?
Rear wiper problem at startup
- Thread starter jimithing
- Start date
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Guess I should have done a google search before I posted. Found this thread:
http://www.toyota-4runner.org/4th-gen-t4rs/100784-rear-wiper-ignition.html
I'll try a new battery and see if it helps. Too bad, I still have the OEM panasonic in my 2007 and was hoping to keep it.
http://www.toyota-4runner.org/4th-gen-t4rs/100784-rear-wiper-ignition.html
I'll try a new battery and see if it helps. Too bad, I still have the OEM panasonic in my 2007 and was hoping to keep it.
BlackWorksInc
New member
Its a weird quirk that happens when the battery is dying; at least from what everyone on the forums has figured out. Toyota doesn't have anything mentioning it in their FSM so I assume its an unintended concequence of the module not recieving enough voltage.
nevada
Senior Member
ive seen weird things like this in other cars with bad batteries, and alternators.
what makes no sense to me is, how is that circuit being closed, if the switch isnt on?
BlackWorksInc
New member
On many modern vehicles these ciruits are controlled by modules, the physical switch does nothing more than provide an input/output signal to the module who then makes the decision on what to do.
i.e. the rear wiper module is probably getting an unstable voltage at cranking and is spazzing out and turns the wiper on for one stroke as it itself is having a stroke.
When the voltage starts spiking, varying wildly, and/or functioning in a non-stable manner the modules can become logic locked, freak out, or any number of strange responses can occur. This is why most European cars light up like Christmas trees when the batteries start getting low because the communication busses and sensors start freaking out and it causes a ton of essentially benign issues that require a factory scantool and a new battery to properly fix.
