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Wipers run constantly
Posted to Technical Tips Forum on 2/1/2017 4 Replies

Vehicle came in with the wipers constantly running low speed with the key on. Off, intermittent and low speeds all run at low speed. Hi runs at high speed. The test for this is to disconnect the wiper switch and if the wipers shut off, replace the wiper switch. I hate tests like this, so I checked voltages at the wiper motor.

Wiper motor has 5 wires. White/black 12v ignition feed, black/orange ground. The remaining 3 wires are black/pink (supplies voltage in low speed), blue/orange (supplies voltage in high speed) and dark green (supplies voltage in intermittent)

Battery voltage at the white/black wire. Voltage drop at the black/orange wire for ground showed .02 volts with motor running. The black/pink wire shows 12 volts at all times EXCEPT in high speed. Blue/orange has 12v only when in high. Dark green never showed any signs of life.

Plugged in a new aftermarket wiper switch only to be disappointed with the same symptoms. Back to the drawing board and second guessing myself on the diagnosis and on the aftermarket switch.

This time I ran my tests at the wiper switch and wanted to test all the wires for the front wiper, rear wiper and washer pump. Back probing the front wiper motor wiring I came up with the same results, then I got to the tan/red wire which is the power feed to the front windshield washer pump. Hmmm 9volts? Wait what? Unplug the switch and I still have 9 volts on the wire. Just for kicks, I hit it with a test light and it did not light.

Ok, lets remove the terminal from the switch and see what happens. With the washer pump wire disconnected, everything works properly (except the washers). Looking to see where the washer pump was, I noticed a broken ground wire on the right side frame rail (sorry alldata did not give me the ground number. Fixing that ground took the 9 volts away and fixed the wipers.

Looking at the wiring diagram, I see S114 on that ground wire. I don"t know where it goes, but I know that is where my stray voltage came from.

After that long winded story, my tip is if you have one of these come in with wipers not shutting off, try the windshield washers. If they don"t work, check the ground on the frame rail right behind the washer filler neck.

And no, I did not leave the switch in the vehicle.

Todd Gangemi
Technician/Manager
First Choice Auto Repair
Voorhees, New Jersey, USA

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car Vehicle Data

2004 Mazda Tribute ES 3.0L

Engine3.0 L
Trans4-speed Automatic (Electronic)