Wiper Park problem, Hep me, hep me?

[55chevy]

My wipers stop almost vertical, before I pull the motor I thought I would ask repair advice.

[nu2-72]

send me your email and I can send you a scan of GM fixes.

[72 longhorn BB]

Can you describe your symptom with a little more detail?

I have an idea what might be the prob, but I want to verify what you are talking about.

I assume you are talking about when you turn off the wipers, they go to rest in the middle of the windshield?

If so, is it always the same spot in the windshield?

[55chevy]

Yes, it stops at same place, about 75 degrees from horizontal, I can get it up to 90 degrees and out of my line of sight by playing with the switch, if I go to far it goes back down and up to stop again.

Chuck, too

chevy55_geo@yahoo.com

[Green Machine]

Has anything been taken apart recently? It's possible to install the arm on the motor 180 deg off. You could try removing the arm from the motor and rotating it 1/2 turn, IIRC there is a mark on the arm and motor that lines up when the motor is parked. This requires cowl removal.

[72 longhorn BB]

Those were my thoughts too.

The wiper park switch is actually a 360 degree circular plate that provides a parallel path to ground for the wiper motor, when the wiper switch is set to off in the middle of a wipe cycle.

Once the switch is turned to OFF, the wiper motor recieves ground path through the wiper park switch until the wiper reached its "parked" position.

That position is about 12 - 15 degrees of rotation (when the wiper arm is near horizontal).

Once the wiper blades are parked, the wiper park switch has entered the non conductive 12 - 15 degree area and the ground path to the motor goes away.

Since your wipers always park at the same place when you turn the switch OFF, it seems that the wiper arm is attached to the wrong place on the shaft.

You should probably take them both off, run the wiper motor, then switch it off. The wiper motor should park in the right position.

Then reattach the wiper arms and verify the fix is correct.

Hope this helps.

[nu2-72]

I cannot get the page to scan at a reasonable size so I will do this.

Turning the dash switch "off"is merely the first step in shutting the wiper off. The wiper motor actually completes the shutting off of the wiper.
When the owner turns the wiper dash switch to the "off" position to shut the wipers off, two simultanious functions are accomplished:
1. The relay coil circuit is opened and this allows the spring loaded relay latch arm to move out into the path of the gear drive pawl. The relay switch contacts, however, are still closed at this stage of operation and the wiper motor continues to run.
2. The shunt field circuit is connected to ground at the dash switch and the wiper operates in "LO" speed during this stage.
The wiper gear mechanism completes the shutting off of the wiper as follows: Since the wiper motor continues to run when the dash switch is turned off, the continuing rotation of the gear causes the drive pawl to engage the relay latch arm. This action unlocks the gear from the drive pawl, lock pawl and the drive plate and output shaft assembly. With the drive plate and output shaft unlocked from the gear, and since the output shaft extends through the gear shaft off center, the continuing rotation of the gear at this point causes a cam action between the output shaft and the gear shaft. This cam action causes the gear drive pawl to move into the relay switch slot. As the drive pawl moves into the switch slot, it pushes the relay latch arm against the the relay switch flexible contact. This action opens the relay switch contacts which cuts the 12 V feed to the motor windings.

Now, having said all that. (repeating what was said earlier) You do seems to have a correct motor and park sequence. It does seem that your arm and motor are not aligned properly.

I agree with the rest of the guys here. If it stops in the same place each time, reset the arm location. If it is changing, check the switch for gound problems and the motor for contact problems.

[55chevy]

Rotated arm 180 degrees, still same problem, arms even run off the bottom. I have a 72 that has the washer pump at top of motor, the 68 is on the side, took motor loose inside but it has only 3 bolts holding it on, can't put the motor on any differently. Still stumped. _\_ <wiper stops here

[nu2-72]

Then I would remove the wiper arms from the two posts. Park the wiper motor and re-install the arms. Trial and error.

[55chevy]

I switched the wiper motors with one from a 72 parts truck, same result, stops half way up the windshield. I am assuming the 68 uses the same motor as a 72? The 72 motors are mounted 90 degrees from a 68, if they don't use the same motor that may be the problem.

[nu2-72]

Can you get a part # from one? My GM book shows; 4911476 as motor assy.
63-66 All w/2 spd (exc. 4wd
63-66 4wd w/2 spd (2nd series)
67-72 Ser. 10 thru 30, Blazer
67-70 G-10-20

And the armature assy. is the same from 62-72 All (2spd w/washer) 4910164
GM manual group 16.064

[55chevy]

number on motor is 5045432, I am going to try to rotate it 120 degrees and see if that is the problem.