It’s 3:00 PM on a Summer Friday. You’re driving for a date you waited for so long. This is not an ordinary date though. You’re already sure your prospect will have no choice but to say yes. You’re after all, driving a Porsche. Everything is perfect except for a dark cloud looming ahead. It does not worry you though because it is one of the normal summer cloudbursts you’re used to. In a minute or two, you will have passed through it. The first raindrop hits your windshield. Instinctively, you turn on your wipers. There is a slight movement, the blades twitch and a few seconds later the wipers’ rubber strips make a swipe across the glass. You end up with bugs and grit smeared into an ugly paste. The wipes seem lazy. They squeak and grown. Then just when you expect a glimmer of hope, the blades stop dead cold and block your vision. The wipers have decided you won’t have a date! You steer your Porsche off the road to a curb and try to figure out things as it starts to pour. Where do you start from?
Check The Fuse
Always start with the fuse. That’s because a wiper assembly system that suddenly stops moving might have a blown fuse. But fuses hardly ever blow on their own especially when it comes to a Porsche windshield wiper motor. There is always something that triggers the blow off. Even when at full stall, the motor’s current draw should be below the fuse’s rating. So even where the fuse is blown, there is usually a high likelihood that something else is wrong. It could be faulty wiring or a shorted wiper motor armature. Both of these problems occur along the harness between the wiper’s motor and the switch. Keep in mind too that even a simple mechanical hitch like seized bushing can cause fuse failure.
Inspect The Commutator
So you have inspected the fuse. As a matter of fact, you replaced it with a new one, complete with the right amp rating. But there’s still no action. Clearly, the problem is elsewhere. That is where the commutator comes in. Turn the ignition and the wipers on then whack the motor assembly with a rubber mallet or the handle of a screw driver. If that gets thing in motion again, you have a faulty commutator. It is easy to understand how this stops wipers. No current flows anytime the motor parks and brushes happen to be sitting on the wrong segment. Whacking the whole system the right way can sometimes jolt things again and create motion. Note that there are several windings on the armature. The motor will therefore run well until the next time it rests on a faulty spot.
A Porsche windshield wiper motor should be easy to lubricate. Unfortunately, this does not appear to be the case with Porsche owners. Ice buildup, lack of adequate lubrication, simple corrosion and sometimes wear and tear can slow things down. A loose joint will for instance, leave lost motion. The bladed will either catch each other and get tangled or flop around. To fix the problem, ensure joints that attach transmission arms to the wiper’s pivot shaft are well lubricated.