Wiper Motor Issue

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SeamusNZ
Posts: 44
Joined: Fri Sep 16, 2016 3:11 pm

Wiper Motor Issue

Unread post by SeamusNZ » Wed Jul 12, 2017 3:11 pm

Hi all from New Zealand,

I have a problem with my single speed wiper motor that someone may be able to help with.

The motor runs ok for about 5 minutes before stopping mid cycle. I have noticed that the motor is heating up a bit and is quite hot by the time it stops. If I move the wipers manually it will go through another cycle and stop again with the wipers half way up the screen. Once the motor has cooled down, it appears to run ok for another short period before shutting down again.

I have checked the ground connection of the switch and have pulled apart and lubed the wiper mechanism up behind the dash. I have checked the motor with a multi-meter and found that it is pulling around 11 volts???

Has anyone had a similar experience and if so, what is the probable fix.

Kind regards...

SeamusNZ

Jerry Whitt
Posts: 567
Joined: Thu Sep 26, 2013 2:42 pm

Re: Wiper Motor Issue

Unread post by Jerry Whitt » Wed Jul 12, 2017 9:14 pm

The term "pulling 11 volts" is an odd term. The charging system on the car usually will hold electrical pressure in the area of 14 volts. The input voltage should be close to the charging voltage. If there is only 11 volts available to the electric motor, that could certainly be an issue.

Terminology is important in troubleshooting:
1. Voltage is measurement of electrical pressure
2. Amperage is measurement of electrical volume
3. Resistance in a circuit is measured in terms of ohms.
Jerry Whitt
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SeamusNZ
Posts: 44
Joined: Fri Sep 16, 2016 3:11 pm

Re: Wiper Motor Issue

Unread post by SeamusNZ » Wed Jul 12, 2017 9:52 pm

Sorry, should have been clearer with my explanation.

With car not running, ignition on and wipers off - voltage reading at wiper motor live terminal 12.68 volts

With car not running, ignition on and wipers on - voltage reading at wiper motor live terminal 10.5 volts

With car running and wipers off - voltage reading at wiper motor live terminal 14.5 volts

With car running and wipers on - voltage reading at wiper motor live terminal 13.2 volts.

My point is that with the wiper motor not operating the voltage readings appear normal.

With the wiper motor running, the voltage at the live terminal drops off 1-2 volts. Is this normal and if not, what does it suggest may be the problem.

Kind regards..SeamusNZ

66vairguy
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Joined: Tue Dec 21, 2010 3:44 pm

Re: Wiper Motor Issue

Unread post by 66vairguy » Thu Jul 13, 2017 3:58 pm

If you are running the wipers on a dry windshield then yes the motor will get HOT. With the wipers running on a wet surface the motor should not slow down and stop. Just a guess, but the windings insulation may be failing due to heat. Again the motor was NOT designed to run wiper on dry glass.

Another possible problem is poor power to ground connections ---- Due to the "park" function (keeps wipers on when you turn the wiper switch off until they are down in the "park" position) power goes to the wiper motor and THEN to the wiper switch which connects the HOT wire(s) from the wiper motor to the dash board ground to turn on the wiper motor. This is a notoriously poor ground after decades due to corrosion (or somebody painting the back of the dash). Also the wiper internal contacts go bad or the circuit board on the back of the wiper switch comes loose creating a poor switch contact. Fortunately all is repairable, BUT removing the wiper switch to check all this is NO fun. With some care you can dismantle, clean, lube the switch - or buy a new one if needed.

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toytron
Posts: 476
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Re: Wiper Motor Issue

Unread post by toytron » Fri Jul 21, 2017 10:19 am

It sounds like there is a problem with the gearbox. The grease in the gearbox is probably the original. Most grease has a clay base. When the oil has leached out of the grease then you are left with clumps of clay with very little lubricating action. You probably need to open it up if possible and clean and inspect it before it gets worse if it is not already.

Ed Stevenson

Edwin Stevenson
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