Had this same problem with a 1974 Datsun 260Z way back in the late 1970s. Turned out to be a small metal contact inside the motor that had grown weak over the years and finally snapped off inside the motor. A new motor assembly was required to fix the issue since Datsun did not sell individual wiper motor parts....

 

well the motor is out again, time to try and understand if it is the Fem, wiring, or ????

 

Just trying to figure out how the wiper work...

See the drawing attached earlier in this thread - hope it is applicable for your year model

1) The wiper motor has internal PARK position switch. When in PARK - you should measure a short between pins FH17-5 and FH17-3. Chek that.

2) When wiper has OPERATE command - Relay R16 (WIPER PARK RELAY) ACTIVATE thus shorting its Normally open contact and allow voltage to reach
R15 (WIPER H/L RELAY) contact 3 - who then distribute the voltage to the Wiper motor.
So when you run the wiper - R16 must activate to provide power to the wiper motor.
taking the relay out will disable the wiper operation...

3) When Wiper need to park - Relay R16 deactivate. In order to let the wiper reach park position - an alternative power loop is provided via the wiper PARK contact. See point 56 (fuse??) that feed contact FH17-4 in order to let the wiper motor run until it reach its park position.
FH17-4 is returned back to R16 via FH17-5 in the wiper motor, this providing alternative power until parked.
When reaching park position - FH17-5 revert to ground thus stopping the Wiper motor.

Since you replaced motors - I assume either:
--> you do not have power to [56] FH17-4
--> you have a wire issue between FH17-5 and R16 pin 4 (check for continuity - easy).

That is the only problem that can be - since once the wiper motor operate - all other stuff is ok!!!!

EDITED: ---> I just see also - the wiper control can be also from the RAIN SENSING unit as well. I don't know if you are fitted with -
but it can be malfunctioning in some way and maybe - just very low possibility - affecting your wiper operation. 99% it doesn't

Please advise - or ask for further help..

 

Thanks Orlee,

Well I have 12.6 volts on 17-4 and I have continuity between 17-5 and the relay pin 4. My 05 has a little different electric diagram (relays R6 and R16) but I believe the wires are in the same location. Also I do have the rain sensor. This is a tough one...

 

Hi Jerry

Once the wiper are at park position - the power at FH17-5 should be cut by the internal wiper switch and send this pin to ground. The motor wiper is fed from this pin once R16 is not energized (end of wiper command)
This is why the wiper stops.

I was referring to the rain module since it is also connected to the same wire - but as sensing the wiper status. I dont think the problem is there. (See wire FHS16)

well, certainly a tough one

Last thing may be the electronic control unit... It senses the wiper power feedback from the relays FH9-13..... and when parked - provide a stop. Maybe that wire that feed-back the electronic is at fault...

 

I hope it is not the control unit, those are expensive !! You know a lot about this stuff, since I have the wiper motor out what pins should I connect pos and neg to so I can test the park portion of the motor. It is the 3rd motor (original, and 2 replacements) but I want to cover all bases. I heard somewhere the ECU could be reset by the dealer and it clears up some odd electrical issues. Do you know anything about that? I assume they would hit me $200-300 for doing it.

 

If I understand correctly - in order to check the PARK switch, Just provide
a (-) to FH17-3, a (+24V) to FH17-2 to run the LOW SPEED motor, and test
the PARK switch between FH17-3 and FH17-5

FH17-5 should provide a short circuit to FH17-3 at park position.
The schema is clear.

Since you replaced 3 motors - I assume you have them working ok.

The ECU provide a very simple interface to both relays - so I do not think you have an issue there.
Can you video the action of the wiper while it is connected to the car? Maybe we will be able to figure out what happens....

 

Don't think you mean +24V!!

 

Orlee, I'll try and post a video tomorrow. I monitored all circuits with relays in and out, motor plugged in and out, wiper switch on and off, all with my meter. Everything seems to check out. One odd thing was when the wipers went from on to off the current on park relay pin 2 jumped up for a second then back to nothing. I would have thought it needed to be energized for much longer. Just a guess .Also when the wipers are turned off they go several wipes before stopping, in the past it seemed it taking but a single wipe before they parked. The saga continues...

 

Too used to 24V...

Yes - might be expensive if applied for too long Ouch!!!

 

One thing is sure - that not how it should work.
The PARK relay should stay energized for the whole time the wiper is ON.
UNLESS MY DIAGRAM IS NOT CORRECT and you have the PARK RELAY action reversed!!
That do not make sense to me.

Once you want to STOP the wiping - the PARK relay should DE-ENERGIZE,
and the wiper motor will keep moving by alternative power supplied via
Wiper motor assembly FH17-5 until it find PARK position where at that moment the FH17-5 contact revert to ground and cut the +12 Volts that was supplied via FH17-4.
The wiper motor park contact role is to make sure that power is applied to keep motor running until parked where power disconnect by the internal park switch.

This is all mechanical actions.
---> Once you activate wipers from inside the car switch- the PARK relay should energize.
--->The moment you STOP the wiper from the wiper control switch in the car - the PARK relay should instantaneously DE-Energize,and wipers should keep moving until parked.

Check this timing - it will tell you if everything is on order - this is the basic.

 

I'll test your suggestions.. here is a video of the wiper mechanism, I don't have the blades on but you can see the action and notice the location of the red dot on the wiper shaft when I start and stop the wipers by the control inside the car.

https://www.dropbox.com/s/v8yy89d4jzh6nsh/VIDEO0011.mp4

 

I did a quick sound test on the park relay... wiper turns on I hear the click, wiper turned off I hear a click, wiper motor stopping running I hear another click. 3 clicks from the park relay doing it several times and the wiper did not end up in park position. I have worked on cars since I was a teenager and never been so frustrated. lol

 

Hi Jerry, there should not be a third click.
I suggest a simple test that will tell you exactly if the control to the PARK relay is ok:

1) remove the park relay
2) connect a 12V test lamp between pins 1 and 2 of the relay socket - this is the relay coil.
3) the lamp should light up when you run the wiper and go out instantly when you stop the wiper from the wiper control knob inside the car.. No delay, no repeats. It's only on-off for that relay straight correlated with the control knob. (via the ECU, but that's how it should work to my opinion)

Everything else doesnt matter. If that relay operate different - we may have an ECU problem / Rain module problem / wiring harness issue.

1) Alternate test, a bit more tricky:
Take out the PARK relay. Connect a toggle switch to the PARK relay contacts and simulate its 2 positions. For that you will remove the relay from it's socket and run 3 wires from the toggle switch to relay socket pins 3,4,5. make sure you connect properly the pin 3 to the Change Over of the toggle switch so as not to short the (+ 12V) with the ground from the wiper module park switch.
One position is RUN, the other is RUN TILL PARKED and STOP.
This is simple as you only need to take out the relay.

I am sure you will learn a lot from such test. It simulate the ECU so if it still doesnt work - you have a motor/mechanical issue and we shall look that way.


EDITED ---> One more thing come to my mind:
Did you grounded firmly the Wiper unit ? If there is no good ground - you may run into tons of weird behavior issues. FH17-3 should be tied to ground firmly.
Can you make sure it is? I mean - check that pin vs ground in the harness connector to car body/ground, not the motor side.

 

Orlee, I did the lamp test. Light came on when the wiper switched turned on, stayed on until about 3-4 seconds AFTER I turned the wiper switch off inside the car. Did not go off immediately. I'll try the other test in a bit... thanks.

 

Orlee, I didn't have the toggle switch but I made up 3 wires, connected them to pins 3,4,5 of park relay. touched 3 and 5 to run the motor for a few seconds then quickly (sub second) connected 3 and 4 together. The motor stopped when I broke the 3, 5 connection and did nothing with the 3,4 connection. I tried this several times both with the ignition on and off, no difference. Do you believe the change from pin 5 to 4 needs to be immediate, sub sub second speed? Also I returned the reconditioned wiper motor and got a brand new one....
On the ground issue you mention it seems good but I connected a wire from the wiper motor case to the body / engine (all have good connections. No difference on the failure to park. ugh.

 

Can you check if you have +12 V on pin FH17-4 - the harness plug side in the Wiper motor assy? I think you do not have that voltage and that is the sole issue.

That is because when you hold 3+4 together when NOT in park position - power should be supplied to the motor until parked via power fed from FH17-4 to FH17-5 to Park relay pin 4 and to the motor via the speed relay.. You do not have that loop working - probably no +12V fed to pin F17-4...

btw- speed for changing from 3-4 to 3-5 is not an issue at all.. take your time - its not important at all.

 

Sorry, I do have 12 volts on pin 4 at all times.

I will retest the loop 3-4 and 3-5 when I am sure motor is not in park location.

 

Something very odd here, I disconnected the motor and put an ohm meter on pins 17-4 and 17-5 of the motor, it shows continuity. The run state I believe. I check socket 17-4 of the plug for the motor it is hot. I check plug socket 17-5 with relay 4 pin and I have continuity. I plug the socket into the motor and at relay pin 4 I am NOT hot. How can this be ??

 

You are at the cause of the issue there.
It look like a bad contact/wire. Under the motor load - the voltage drop to zero. With open contact you see the hot indication. This is how it look like. Anyway - the whole behavior of the wipers seems to originate from that signal. Keep investigating there - at least it focus you at where to put efforts.
I suspect the HOT indication on the socket 17-4 is under no load - it will drop to zero under load due to wiring harness issue there. it can not bear the load of the motor. Check carefully the wire that goes to FH17-5 - try to pull it out - maybe you can re-wire it. Same for the section between FH17-4 and relay pin 4 - might be a loose wire there

At least - it seems all the electronic is fine...