Another wiper motor question

[Andy4639]

Originally Posted by RustyPile

This has been going on for a year, it's time we get those wipers working..

The yellow wire comes from the "Ignition on" terminals in the fuse box and carries voltage to the wiper motor.. The switch provides the ground path through the 2 blue wires for each speed.. The switch HAS TO BE GROUNDED TO THE DASH.. The yellow wire is hot with the ignition switch in the ON position.. If there is no voltage present on the yellow wire, there is an open (as opposed to a short) or bad connection somewhere.. Find the open, (don't forget the fuse and it's connections) repair it, and the wiper motor should work..

Good info. The wiper is hot all the time. The dash switch makes ground for it to work. You have to have the wiper switch grounded to the dash for it to work.

[RustyPile]

Just so everyone is clear on this point: The yellow wire is hot only when the ignition switch is in the ON or ACC. position..

[HIGHWAY BY THE SEA]

Originally Posted by RustyPile

Just so everyone is clear on this point: The yellow wire is hot only when the ignition switch is in the ON or ACC. position..

Yes, I tested them with a meter today, and they are both hot when I turn the switch into the ON position, but not the ACC for some reason. Mine is a 67, but the ignition is 68 & up.
I am beginning to believe that the new wiper motor itself is bad because I have already checked the ground for it multiple times, and used a ground jumper wire directly to the body (and negative battery terminal). Looks like I will be removing the motor today if the rain stays away.
This thing worked very poorly when I first installed it (too slow, then NOTHING) so on to the next thing...

[HIGHWAY BY THE SEA]

I traded in my non-working wiper motor for a new one that bench-tested operational.

Then I tested my wiper plugs with a volt meter today. Here is the output (set on 25 DC)


Here is the meter (set on 25 DC) directly on the battery posts. The output is far more than on the wiper plugs. Is this normal?

[RustyPile]

As stated above, voltage is fed directly to the motor from the fuse box, and the switch provides the ground.. If you're checking voltage on the plugs at the switch, you'll get readings below battery voltage because of resistance in the motor windings.. Your test only verifies that you have voltage applied to the motor.. Does nothing toward testing the motor or switch..

It appears you still don't understand how the system works.. Read my first post in this thread again...

[HIGHWAY BY THE SEA]

Originally Posted by RustyPile

As stated above, voltage is fed directly to the motor from the fuse box, and the switch provides the ground.. If you're checking voltage on the plugs at the switch, you'll get readings below battery voltage because of resistance in the motor windings.. Your test only verifies that you have voltage applied to the motor.. Does nothing toward testing the motor or switch..

It appears you still don't understand how the system works.. Read my first post in this thread again...

Yes, I most certainly do NOT understand how this system works.
I have proven that the wiper motor works bench-tested, that I have sufficient power running to it, that my wiper wire plugs are good, that it is hooked up correctly (wiring diagram confirmed), that it is properly grounded, that I have a brand new wiper switch, and with all of this I STILL do not have a wiper motor that works when hooked up to my wiring!!!!
I re-read your post, and as far as I can tell I have done everything correctly, and I TOTALLY do NOT understand any of this because this thing is not working!!!! This is very frustrating to me, because I no longer know what else to do.

[RustyPile]

Ok, I understand.. Electrical stuff can get confusing.. Those electrons running through the wires are invisible.. Unlike water, we can/t see where they're going when they leak out..

Let's try this again.. The yellow wire at the wiper motor carries voltage (those electrons) straight to the wiper motor.. It doesn't go any where else (no switches) nor does it stop (go through a relay) along the way.. It's hot only when the ignition switch is in the ON position, or in the case of later models, it's hot also when the ignition switch is in the ACC position... For now, let's not worry about the ACC position.. The reason for this design is so that when the wiper switch is turned off the wiper motor will continue to run until the wipers reach their park position..

There are 2 sets of windings in the motor -- one for high speed and one for low.The windings are not grounded in the motor. Instead, the ground side of the windings are carried through the harness to the wiper switch.. When the wiper switch is turned on, it provides the ground path for the winding speed selected.. As such, the wiper switch must be firmly grounded to the dash.

Disconnect the harness at both the switch and wiper and test each wire for continuity.. There are three wires -- dark blue, light blue, and black.. Disconnect the battery for this test. If there is voltage present on the wires, you can ruin the voltmeter.. Set the volt meter for continuity, and probe each wire.. You should see full scale needle deflection on an analog meter, or in the case of a digital meter, an audible alarm..

IF you have good wiring, good motor, good switch, and a GOOD ground, your wipers should work.. .