On 4/06/2012 10:25 p.m., Dave Plowman (News) wrote:
In ,
Gib wrote:
The wiper fuse blew on my Toyota Camry wagon when I activated the rear
wiper. I've taken the motor off and looked inside - no obvious
problems. I'm wondering what electrical testing I can do with an
ohmmeter. The complication is the relay unit, which has six
connections. I'm not sure how it operates.

Most rear wipers have an intermittent setting. Maybe also a timed cycle
when using the washer, if it has one. So the 'relay' unit would have
connections to the switch as well as the motor. The timer unit on my SD1
which has both these functions has 6 connections.

But what you need is a circuit diagram for your model. You could then test
the motor directly from the battery to ascertain whether it's that or the
timer causing the problem. Was there any smell of burning when you looked
at the motor?


I have a kind of generic circuit diagram, which doesn't convey a great
deal to me. I think you're right about the timer. I tested the motor
directly on the battery. Initially there were big sparks (the
fuse-blowing kind), then it went open circuit. Not a good sign. I
think I may need a new wiper motor.

While testing things I noticed my battery voltage was very high (I'd
just been running the engine). With the engine running the charging
voltage is about 19v. A new, probably more serious, problem. It's a
bit of a coincidence, so I'm wondering if they are linked. Could the
high battery voltage have caused the motor to fail? I'm familiar with
low or no voltage from the alternator, but I don't know what can cause a
high voltage.