Auto Repair - Other

Diy Automotive Repair how to Repair Windshield Wipers



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Having trouble with your windshield wipers? Since wiper trouble could be anything from needing new wiper blades to needing a new wiper motor, linkage, wiring, a switch, relay or a fuse, you must first do a little trouble-shooting. The first thing to determine is exactly what is the problem with your wipers. When you turn them on, does anything happen? If you see smoke, look where it's coming from and that is probably the source of your problem. That is likely the easiest diagnosis you could get. If there is no smoke, forget about your plans to collect the insurance money and go on with your trouble-shooting.

If the wipers work basically normally but don't clear the windshield, it sounds like simple wiper blade replacement is all you need. If you can't figure this out, you have no business even trying to work on a car. Chances are the store or gas station you buy your new wiper blades from can change them for you.

If they fail to do anything, check carefully and see if they even try to move a bit. It is easier at this point to have one person inside turning the wipers on and off as you instruct, while you carefully examine the wipers themselves. If they are trying to move, but don't do anything more than wiggle slightly, chances are either the wiper motor or wiper pivots are seized, or something is jamming them. You have eliminated the possibility of a lack of electrical power. They wouldn't move at all if there were no power. If they wiggle but won't do more, unbolt the wiper motor from the car and try moving the wipers by hand. They should move freely. If they do, your problem was with the wiper motor. Replace it. If they don't move now, the problem is likely the pivots (the point where the wiper arms attach to the car). First try spraying a good penetrating oil in and around the pivots and try to work the arms back and forth. If they don't move, they may have to be unbolted from the car and soaked in penetrating oil overnight. Since almost every car is different in the way these pivots are attached, if you can't easily figure it out by looking, consult a shop manual for directions.

If the pivots are moving freely, but the arms don't move, the problem is most likely your wiper motor. First check for power. As in the previous example, if it tries to move, you must have power, but if it doesn't, a simple test light will help here. Ground the clip end of the test light and touch the pointy end to the wire connections at the motor. You should consult a wiring diagram to tell you which wires should have power. Have your helper turn on the wipers from inside the car. If you have power there but the wipers don't work, replace the wiper motor. They are usually held on by two or three bolts and are easily accessible on most vehicles. Again, if you can't figure it out, consult your trusty shop manual, since this differs from vehicle to vehicle. Most parts replacement is common sense. The difficulty is making a correct diagnosis.

Now on to the harder issues. If you have no power at the wiper motor when your friend turned it on, make sure they weren't just joking around with you, and that they actually turned it on. Assuming they really did and it still had no power, check the fuse. Fuseboxes are another thing that vary from car to car, so search around under the dash, or in the glove box for the fusebox. If you can't find it, when you are looking in the glove box, grab the owner's manual and it should tell you where the fuse box is hiding on your particular vehicle.

The old fashioned way of checking a fuse is to simply look at it to see if its filament is broken, indicating a blown fuse. Most newer cars however have fuses that are virtually impossible to see the filament in, without removing them. I believe they call that progress. You could remove each fuse one by one, (unless your owner's manual or fuse box lid tells you which one is for the wipers), and check the removed fuse's condition. Another way is to use your handy dandy test light and with the clip end grounded, touch the pointy end to the contact on each side of the fuse. With the power on and wipers switched on, there should be power to both sides of the fuse. If there isn't, pull out the fuse and inspect it. Replace it with the same amperage of fuse if it is blown. If that was all your problem was, your wipers should work fine now.

If your fuse was good and the wiper motor still doesn't have power, check to make sure you have power at the switch. Power goes from the fuse through the switch and then to the motor. If the switch is inside the steering column like on most newer vehicles, as part of what is called a multi-function switch, you must disassemble part of the steering column to gain access to the switch before you can test it for power. On most newer cars the steering column is covered by plastic sleeves that are in two pieces. Simply undo the screws holding the two halves together and you should see the switch assembly. You will require a wiring diagram to figure out which wire(s) should have power. There are a lot of wires at these type of switches.

If your car has a simple dash mounted wiper switch, access to it should be almost painless. Once you get to the wiring connections, make sure they are connected well, and check for power with the wipers turned on. These are a simpler type of switch and you may not even need a wiring diagram to figure it out. If there is power going in and nothing coming out, then replace the switch.

Chances are the problem will be either the fuse, the motor, or the switch, but failing that it could either be a broken wire or a relay. These should show up on the wiring diagram, which you will need at this point, if not before. A relay works like a switch itself. If you have power coming into the relay, but nothing coming out, replace the relay. They just plug in and usually require no tools, just fingers.

If you have confirmed that there is indeed power coming out of the fuse and not going into the switch, or power coming out of the switch but not going to the wiper motor, chances are you have a broken wire. Now you really need a wiring diagram because automotive wiring is all color coded. Your wiring diagram will tell you which of the thousands of wires travel between which components. Follow each wire that should have power and look for any breaks, or burnt coating and replace as necessary.

One important thing to remember is to disconnect the battery before attempting any electrical repairs. It is necessary to have the power hooked up to do the testing, but disconnect one terminal (either will do, but I prefer the negative or ground) before making repairs. If you touch a live wire to the body, it will arc and that can cause further electrical problems. When you locate the broken wire, replace it. Hook the battery back up and your wipers should work once again.

More about this author: Bruce Saalmans

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