Bench Testing Wiper Motor

[Jimmy240Z]

Is there a way to bench test a wiper motor to see if it is working? I was thinking that using the battery, I could apply power to the LR (Power Source) and a ground back to the battery via B (Ground) but what do I do about the LW (To Relay), L (Low) and LY (High). I assume that they are some how related to the 2 or 3 speeds of the motor. If anyone knows how to do this I would appreciate the help.

r/,

Jimmy

[Bambikiller240]

COuldn't you just unplug the motor currently in your car, and plug in the one you want to test, then operate the switch?

[Jimmy240Z]

The real problem is that the previous owner stripped the plug off of both the motor and the wiring harness. I think but I'm not sure there is a problem with the wiring harness to the wiper motor. What I am trying to validate is how does the motor actually work and then what is wrong with the harness.

[gundee]

Wires LW, LY, L, B all go back to the wiper switch. No relays involved. You would have to make a switching device to simulate the wiper sw. As that is not practicle the best is to find or borrow another switch to hook the wires to and do your test.

[TomoHawk]

I would just hammer a line (or two) of naills into a board, then attach the wiring harness and use patch wires to simulate the switch.

Document the circuit and then email a copy to everyone here- or at least ME.

thx

[wal280z]

The real problem is that the previous owner stripped the plug off of both the motor and the wiring harness. I think but I'm not sure there is a problem with the wiring harness to the wiper motor. What I am trying to validate is how does the motor actually work and then what is wrong with the harness.

I recall before the updated forum format, there was a 240Z wiring diagram available in the download section. Can't find it now

I think I have it saved on the home computer. I'll check tonight.

Wayne

[Zrush]

What would be the cause of the wipers remaining up on the windshield when you turn them off? This is in a 77 280Z. Is it a simple fix?

Vicky

[Bambikiller240]

What would be the cause of the wipers remaining up on the windshield when you turn them off? This is in a 77 280Z. Is it a simple fix?

Vicky

I currently have my 240Z wipers all torn apart and being rebuilt, and documenting the process. The only 2 thngs I can see that would cause that would be either the mechanical connector to the wiper motor being installed 180 degress from how it should be, or the spring in that connector assembly being broken, allowing the connection to rotate out of normal position. Some day I'll have a "How to" article for 240Z's on this subject. I wouldn't think that 280Z's could be significantly different.

[ChrisA]

Carl and Vicky, on my 72 I can stop the wipers at the top of their arc if I shut the switch off at the right moment. I usually do it on accident and I have to turn the switch on and then off quickly and they'll park at the cowl. I just figured this was a Z quirk.

Chris

[EScanlon]

The wiper motor has a small "cap" on the backside of the transmission housing, to which a pair of wires are attached. That cap is held on to the transmission with 3 screws if I recall right. Loosening those screws (NOT removing) allows you to rotate that cap. By rotating that cap, you'll allow the motor to continue receiving juice, even though the switch has been turned off, UNTIL it reaches the "Park" position. Once the wipers have reached the park position, the contact inside that cap will cut off the power to the motor.

If your wipers ALWAYS shut off at whatever point you turned the switch off, it is more than likely a fault in those two wires. If on the other hand, it's only at ~certain~ positions that the wipers do NOT return to park, it's probably dirt / gunk inside this switch cap.

Enrique

[ChrisA]

The wiper motor has a small "cap" on the backside of the transmission housing, to which a pair of wires are attached. That cap is held on to the transmission with 3 screws if I recall right. Loosening those screws (NOT removing) allows you to rotate that cap. By rotating that cap, you'll allow the motor to continue receiving juice, even though the switch has been turned off, UNTIL it reaches the "Park" position. Once the wipers have reached the park position, the contact inside that cap will cut off the power to the motor.

If your wipers ALWAYS shut off at whatever point you turned the switch off, it is more than likely a fault in those two wires. If on the other hand, it's only at ~certain~ positions that the wipers do NOT return to park, it's probably dirt / gunk inside this switch cap.

Enrique

Thanks Enrique, that is some of the most useful info I've ever gleaned here yet. Can I get to this cap without taking the motor out of the car?

Thanks,

Chris

[EScanlon]

I'm posting a picture from my Clymer Manual that details it out very well. It also gives the location measurements for the Park and fully extended positions of the wipers.

Enrique