The wipers on my 1973 Plymouth Scamp do work properly. It is a 3 speed wiper motor and they work intermittently or not at all. I checked the FSM and first tested the motor, which passed test 1 (continuous wiping) and then went on to test 2 (testing for PARK) this test passed as well. I then tested the same things at the socket in the dash and it too passed. So I'm left with a faulty switch, correct? The FSM is confusing to me regarding testing the switch but is it safe to assume that with the other two tests working fine it is the switch? If so ca it fix the switch? If not where would a switch be available?

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Thanks

Bruce
'73 Ply Scamp 225 1bbl

First off, I'd check that the switch and dash are grounded properly - while the 2sp generally does not require switch ground, the 3sp generally does.

Next, I'd check the bulkhead connections for corrosion; if they're OK and the connections at the motor seem OK, only then would I pull the switch and carefully examine the connector. Often, the connections are the problem.

Check the switch and check it against the truth table in the FSM. Only if fails that test would I replace it. You can get most of the switches still, but those that are hard to find you can often repair them yourself (see http://www.tidewatermoparclub.com/TECH/dimmer3c.pdf for an example of switch repair), but it requires great care and a good working environment. Good luck.

Thanks for the help. I grounded the switch in the dash with a separate wire and still the wipers don't work. I also inspected for a loose connection at the switch and it seems tight. I did test the motor per the FSM, testing both continuous wiping and doing the second test to test for parking. The motor passed both tests, at the bulkhead connection and the dash connection. So this tells me the motor and wiring is working. Is this correct?

As for the switch it is a three speed and you mentioned checking the switch against the truth table in the FSM. I assume that is the continuity test outlined in my FSM. I attached an image of what is in my FSM, you may want to click on and zoom in to see clearly. How to do this is not clear based on the instructions. The connections are labeled differently and I'm not sure which connection to test at what switch setting. As you’ll see some connections are labeled differently than what is on my switch.

_________________
Thanks

Bruce
'73 Ply Scamp 225 1bbl

Yes, you're on the right track. I used jargon in calling that chart a truth table; my apology.

Since B and B/U are always electrically the same, I suppose yours just lacks the B/U pin; don't worry about it (it's probably just an output on the low side of the internal breaker and was used to power an external wiper switch). W is usually for washer; it should short to B when the shaft is pushed in (maybe not in OFF).

If B doesn't connect to anything, the internal breaker may have broken. If the bimetalic strip's spot weld broke, it's very hard to fix - I'd short it out and just use an external auto-resetting breaker in its place. If the points are just burned, you can clean them.

It is best to use a multimeter with buzzer or a self-powered test light; you want all connections (except the resistor) to be less than 1 ohm; the resistor less than ~30ohms (probably - I don't have the FSM in front of me). It should change when you rotate the shaft.

Just follow the chart. For example, with the switch in LOW, B-A should short (0ohms), F1 ought to go through the variable reistor to A (0-~30ohms), F2 ought to short to the case (ground), P ought to connect to nothing.

Check all the positions; don't be fooled by flaky connections; here, you need <1ohm for everything but the resistor; anything over 1K ohm is essentially open, but I'd expect you'd see at least Mohms or offscale for opens. I'd test each position a couple of times to make sure they're reliable.

If you find a poor connection, you can

1) get a new switch (similar switches might work, but check the charts and pinouts 1st!)
2) fill it with WD40 and try to clean it that way (drain it before putting it back)
3) take it apart carefully and try repair it

I've had good luck with #2. Unlike many switch cleaners it doesn't attack most plastics, but it is *slightly* combustible so I'd drain it first. Other people may give you other advice, but my experience with has been excellent.

#3 requires a lot of patience and care not to loose the little springs & balls that will want to shoot out. With it apart, you can use agressive contact cleaners & preservatives on the metal contacts. You might want to glance at http://www.tidewatermoparclub.com/TECH/dimmer3c.pdf as an example of fixing something similar.

I've done a couple of 2sp/3sp hybrid systems, and I do not recommend you try to convert to 2sp or hybrid; it's a lot of work.

Success! I tested the switch with your instructions and got some strange readings. I decided to take the switch apart and it was very dirty. I cleaned it up and put it back together. It passed all tests with the meter and back into the car it went and all works fine. Thanks for all your help.

_________________
Thanks

Bruce
'73 Ply Scamp 225 1bbl