Testing rear wiper motor on Toyota Ice

[toyoldboy]

This is a first post to the Toyota Club.

I want to diagnose why the rear wiper motor doesn't work on my daughter's 2011 Toyota Ice.  The rear screen water pump works, which presumes the fuse is OK.

Lots of general stuff on the 'net, but while educational, doesn't give guidance.

Thought I'd try here to save time.

What should the colours be in the three pin connector?  I have a blurred pic on phone, and can't look for them currently as the car is not here. I guess the positive from the multimeter should go to one of the pins and then the negative to earth to get voltage and circuit continuity.

If it's a good supply, what readings should I expect?

 

 

 

 

[mrfixer]

There should be a three pin connector to the wiper motor.

One terminal will be an ignition-switched live. One is 12V supply switched by the wiper stalk.  The third terminal is ground.

Switch the ignition on and wiper off and use your voltmeter to check for 12V between one of the terminals and a known good earth. Other two terminals should show 0V. 

Now switch the rear wiper on. You should now find another terminal is at 12V. 

Finally the third terminal is the motor ground. Use your meter's resistance range to check for continuity between this terminal and a known good ground.

[toyoldboy]

Excellent, thanks.  I'll do that when the car is available.

[toyoldboy]

If mrfixer is still around, I tried the suggestions today - the first time I've had access to the car since last August.

There is a 12v reading, but nothing comes up on the other two suggestions.  The fuses (20amp and 7.5amp), seem OK on a multimeter continuity reading.

What's next to check - presumably the switch is faulty?

[flash22]

Power is direct to the motor, so you should get a solid 12v, verify your ground between the plug and the body by resistance, check the 12v using the body as ground verifying this with the boot open and closed

+B - Battery voltage

+1 - switch voltage

E - ground

 

if the car has been sat, work the switch back and forth for a good few minutes (same goes for the indicator stalk)

 

 

 

[toyoldboy]

Just seen this, so apologies for the delay and thanks for getting back.

I have the car tonight/tomorrow, so will check again, with the boot closed for verification.  The fuses are still OK on the multimeter, and I've worked the wiper switches.  The car is in regular use, but the rear wiper hasn't been used for a while to I'll have another go before it gets dark.  The rear screen wash works fine.

More later.

 

[toyoldboy]

Update Sunday 22 May '22.  No voltage to wiper motor switch.  Going to work the switch a bit more.

[flash22]

Replace the fuse, it may just have a hairline crack in it

[SimonIG10]

if the fuse is good, it could be a wiring break. Favourite would be where it enters the hatchback from the car. Maybe has snapped after many years of opening/closing. I recall something like this years ago on a Clio we had.