trying to figure out wiring for windshield wipers

[rockycoastcruises]

I have a 87 Albin 27 Sport Cruiser. My wiper motors are malfunctioning as well as the panel toggle switch. At this point I'm starting at the switch and trying to figure out how the wiring goes from there out to the two wipers. If anybody has a schematic or description that might be helpful it would save me some time and headache.
Thanks,
Joe

[Ambler27FC]

I have an 87 FC. I've never seen a wiring diagram, but it is a relatively simple circuit. 12VDC and a ground going through a breaker, then to the switch and to your wipers. If the problem is both wipers, it is most likely in the console. A bad switch, or a loose terminal - a loose terminal being more likely if you've had hands behind the console recently.

The wire run is looks difficult, going into the forward bulkhead and up the window channels. Perhaps best to check resistance across the wires first? If you do try to run new wires, please post details.

I did have an odd issue where one of my wipers would continue running after they were turned off. I "fixed" this by disconnecting the motor ground wire. This is poor practice, but has worked so well that I've forgot to buy a new wiper motor (pretty sure this is where the problem is). The wiper motors are still available, but not cheap.

[WillieC]

The park feature is the confusing element for many. There is a hot wire to the wiper motor that keeps the motor running until it returns to the park/off position. If your wipers and windshield are too slick, the momentum can carry the blade past the park/off position and the wiper keeps on a-running. Yes, disconnecting the ground stops the wiper where it is.

Not a wiring diagram, sorry. Hope the description helps a bit.

[rockycoastcruises]

Thanks for the information. I picked up a new switch today and will let you know what I figure out.

[SalishAire]

Here is the wiring diagram for a very common wiper motor:

[Burton]

Our A25 has a wiring diagram on the inside of the door panel that accesses the wiring. Our boat’s wiring was all bad— corrosion back into the full length of most wires, so I ripped it all out. The wipers, short nav light “mast”, and port nav light wiring all go through much too tight channels at the windshield. Other owners have pulled new wire through. With the advice of a marine electrician friend, we are running conduit that will give more space for wires.

The terminal ends of the original wiring on Slow Motion were automotive style and not sealed. With electrons flowing the wires heat slightly. As they cool, moist air is drawn into the wires, resulting In corrosion back even six feet or more.
If wire ends look chalky, it is time to rewire. The nav “mast” light wiring is especially vulnerable due to its location. We had evidence of water entrance there that also got the wiper wire.

The new standard for 12 V wiring is that a ground wire should be yellow. The problem is that a black wire for hot on shore power on the boat can be mistaken for a ground wire in the 12 V system. This can get people killed.

[rockycoastcruises]

So I replaced both wiper motors with identical one speed motors. I replaced the switch in the dash that showed signs of corrosion and was faulty. I also cleaned up/replaced the wiring feeding to the switch - cut back a few inches and even added some wire so it was easier to get the switch out and work on it. I used a double throw/double pole switch so I can run one wiper or both. The result is that the starboard wiper works at normal speed but the port wiper works around half speed. - similar to the motor I replaced. Each motor is getting the same voltage reading, each setup on the windshield is identical. It is a mystery to me as to why the port side wiper operates so slowly compared to the starboard wiper. Not sure about what else to check. "My wiper" works fine but would like to figure this out. If anybody has any thoughts please let me know. Thanks.

[WillieC]

Nice work. Check all your connections. Again. Ordinarily a DC motor runs at the speed it was wound for for at its applied voltage. There may be different taps to change speed but not likely in this application. It may be that you have two identical motors, from outside appearance, but wound for different speed internally. Or the gearing is different in the housing for a different application. (Or you have a huge voltage drop to the second motor. Check voltage at both motors when they are running, if you can get at the terminal.)

Don't you just love figuring this all out? Sometimes I get to the point where I say, Close enough. It works.

I just had to run down a steaming light that worked fine two weeks ago to nothing now. As I was sitting on the ramp waiting for the high tide to launch. No pressure.

Long story, but it was the perfect case of a high impedance in a low voltage circuit. The meter would read 12V at the socket, but it wouldn't light the lamp. All volts and no current. Bad wire. EZ fix (since I had the foresight to pull an extra wire, just in case) but my thinking got stuck on the fact that I had voltage at the socket, this after trying five different lamps in the socket to no avail. Not too bright, mr electrician. As our launch window was closing.

Fixed it in fifteen minutes the next day.

[rockycoastcruises]

Your experience with your light is all too common and never seems to make sense. It funny (actually not funny) how electricity works. I do much better with things that I can see. You are smart to figure this stuff out.
I hear you about the wiper motor. They both read 12v at the terminals while working. since the last one ran slower than the starboard side I'm guessing that it might have to do with the wiring that is nicely run behind the fiberglass channel with no access. When I'm not using it the motor works fine so that might be where it stands for a while. My side works so I need to stay focused on my priorities.
Thanks for your input and happy cruising out there in Washington.

[WillieC]

That's funny. Our port wiper went out. I replaced it with a manual, hand-operated wiper, you know with the lever inside in place of the motor. All the juice with no second motor to share with works the single wiper just fine. (The wipers are still crappy. Good thing we top out at 6 knots.)

If you are getting a good 12V at both motor terminals when running, I would leave the wiring alone. When running, you are reading the voltage drop across the motor. It's got all 12V and it is using them. (You can check parts of the circuit in the same way. When running, check the voltage on both sides of the switch. Or a chunk of wire, check both ends. I've found 2V drop reading the difference at a battery cable and its terminal 1/4" away. Those 2 volts are unavailable to the rest of the circuit.) You may simply have a tired motor, and that might show up with reading the current draw of both motors. However, higher current draw could indicate one side has more drag on it. Different wiper, wetter windshield, length, more pressure against the windshield?

[rockycoastcruises]

I like the manual wiper. No problems with electric on that one. However it will only operate as well as the crew is interested in keeping it working. Keep the whip handy. I appreciate your thoughts and perhaps next winter when I am bored I can revisit this issue. Bigger things to move onto.