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Ford Mustang V6 and Mustang GT 1994-2014: Windshield Wiper Problems Diagnostic Guide

No one likes dealing with broken windshield wipers. This article aims to provide you with all the information you need in order to diagnose and repair the problem causing windshield wiper failure.

By Neftali Medina - September 24, 2015
Contributors: Justanswer

This article applies to the Ford Mustang V6 and Mustang GT (1994-2014).

The windshield wipers on a car are like the big toes on people's feet, we forget how important they are in normal operation of the vehicle. When they fail, it is nearly impossible to drive in rain or during bouts of high humidity. There are several components that come together to make the wipers on your car function, and each part has certain symptoms that usually point to its failure. This guide explains each of those symptoms are their causes, so you can easily diagnose why the windshield wipers on your pony no longer functions.

Material Needed

  • Multimeter

Step 1 – Check the wiper relay

One of the relays may be damaged.

There are two relays located inside the fuse box of your car. The intermediate relay and high/low relay are positioned next to each other. You can test them by using a multimeter and reading the current flowing through them. Some symptoms of a bad relay include:

  • Non-working intermediate setting.
  • Non-working high/low settings.
  • Issues in re-positioning the wipers when they are turned off.
  • No power from any of the settings on the wipers.
Figure 1. These are the relay locations for the wipers on your Mustang.

Pro Tip

A quick and easy way to check if the relays are the problem is to replace them with working units. If the problem is solved, then you are finished!

Step 2 – Check your switch

The switch may have shorted.

The switches on these cars have been prone to fail. A quick way to check it is to remove the steering wheel covers and inspect the contacts from the switch. Grab it and wriggle it around to see if the contacts are loose. If the windshield wipers work, you can either secure in place or replace the unit. Some common symptoms of a failed wiper switch include:

  • Non-functioning high/low settings.
  • Non-functioning intermediate settings.
  • Wipers erratically turn on by themselves.
  • Wipers do not function at all.
Figure 2. The wiper switch for your Ford Mustang.

Step 3 – Check the motor

The motor may have failed.

Although some of the other symptoms may be a bit vague, the motor is generally easier to spot. Instead of an abrupt failure, the windshield wipers will being to slow down or decrease in power. If the motor is damaged, you'll have to access it under the cowl of the engine bay and replace the unit. Specific symptoms of a worn wiper motor are listed below.

  • Wipers slow down in speed.
  • Wipers do not reset properly.
  • Wiper may stop functioning completely while in mid-wipe.
  • Wipers may stutter, as if there is too much resistance.
Figure 3. The windshield wiper motor on your Ford Mustang.

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