Wipers do not return to park position

[P.J. Romano]

I normally do not drive my GT when it is raining but I got caught by shower the other day.
I noticed that the wipers are not automatically returning to park position any more. Otherwise, the wipers work fine, both speeds, just not returning when switched off. As I said, this was fine before...
Visual inspection of contacts on the wiper motor and on the washer foot pedal did not show anything unusual.
Which wire/contact (see the attached schematics) is responsible for the park position? Any other advice would be apprecciated.

[hrcollinsjr]

P.J.,

The DESTEC diagram says the 14 ga. green wire stops the wipers in the down position. I'm wondering if your wiper motor isn't grounded very well.

HTH,
Harold

[Aardvaark]

You say there were okay. Were the arms removed from the shafts for any reason?
Where the wiper arms re-installed with the motor not in in the parked position or
installed up a bit from the cowel?
I don't believe they are "keyed" to the shafts on the GT are they?
Just asking.
Btw. Looking at your album pics, that is one sweet GT you own!

[P.J. Romano]

Originally Posted by Aardvaark You say there were okay. Were the arms removed from the shafts for any reason? Where the wiper arms re-installed with the motor not in in the parked position or installed up a bit from the cowel? I don't believe they are "keyed" to the shafts on the GT are they? Just asking. Btw. Looking at your album pics, that is one sweet GT you own!

It is not mechanical problem, wipers are working fine, just not returning to park position. I am pretty sure that it is electrical issue. Now when Harold identified the green wire as a possible culprit, I will follow that lead. I am somehow suspecting that it lost contact in that white connector under the instrument panel. The worst case scenario should be if it lost contact at the wiper switch. That will require removal of the instrument panel - hate that job. I will make a quick check of the white connector this afternoon and inform.

Thanks for the compliment on the car.

PJ

[wrench459]

It looks like the green wire has power whenever the key is on.
When the outer ring opens the connection between the green and yellow it parks.

I "think" if I'm reading it correctly.

[hrcollinsjr]

Originally Posted by wrench459 It looks like the green wire has power whenever the key is on. I "think" if I'm reading it correctly.

And the wiper switch is in the "off" position.

Harold

[P.J. Romano]

Green wire is dead. Probed it on the both sides of white connector.
Next stop: Wiper switch. The wire could have come off the switch. This will require removal of the instrument panel. That can wait until I return from the business trip...

[wrench459]

Originally Posted by hrcollinsjr And the wiper switch is in the "off" position. Harold

Got ya... I missed it using the 73 FSM wish I had a DESTEC wiring diagram.
What about when the rocker switch is in the low speed position?
Wont the green become hot then also?

[hrcollinsjr]

Originally Posted by wrench459 Got ya... I missed it using the 73 FSM wish I had a DESTEC wiring diagram. What about when the rocker switch is in the low speed position? Wont the green become hot then also?

Nope! This alone is testament to the DESTEC wiring diagram. If I can read it and half way understand it must be good. I should have brought mine to the GA meet for you to look at. You'd HAVE to have one if you saw it.

Harold

[markandson]

There is a very good possibility that the rotating contacts inside the motor have either got old hard grease on them or they may have blown apart the same way a circuit board conductor does. I have disassembled several motors and cleaned the old grease out and re-lubed them, I have found 2 so far that have the blown contact or contact follower problem. The follower or contact finger is a thin copper spring that sits on conductors that rotate when the motor turns. I would bet on the motor being bad, not the wiring. BTW, you won't believe how much better your wipers will work if you take the motor apart and clean it and relube it. I don't drive my GT in the rain either, although I did get caught in a downpour this past Carlisle so it sure is nice to have wipers that work well when you need them.

[jlthunder]

Jeff;

What grease did you use? I'd like to rebuild my wipermotor this winter.

[DESTEC]

There is an "Open-seeking" switch inside the WW Motor transmission. It shows up on my diagram. the green wire, via the open seeking switch supplies 12 volts to the WW Motor when you switch the motor OFF. IF it's OFF and the blades aren't parked or stopped down, the green wire runs the motor unitl it hits the OPEN on the slip ring and the motor stops. ALSO REUIRED:The blue wire puts a ground (yes, a blue GND wire) on this ring to further collapse the magnetic filed of the motor so it does not run out of the OPEN in the slip ring--'cause the blades would go on forever with out the blue wire. One has to pull the WW Motor and take the plate off the worm-gear drive and check the 3 contact arms: clean, adjust, lube and reassemble

[markandson]

Originally Posted by jlthunder Jeff; What grease did you use? I'd like to rebuild my wipermotor this winter.

Jeff, I think I just used white lithium grease, nothing special.

[wrench459]

Originally Posted by DESTEC ...the green wire runs the motor unitl it hits the OPEN on the slip ring and the motor stops. ALSO REUIRED:The blue wire puts a ground (yes, a blue GND wire) on this ring to further collapse the magnetic filed of the motor so it does not run out of the OPEN in the slip ring--

Thanks for the info
I was wondering about that inner slip ring(blue) and how it ties together.
Is the schematic still available for purchase? I'm left thinking hows the foot pump is involved/or hows its wired to be more exact.
The factory diagrams leaves these little details out and I hate letting the smoke out of black boxs.

[markandson]

Originally Posted by wrench459 Thanks for the info I was wondering about that inner slip ring(blue) and how it ties together. Is the schematic still available for purchase? I'm left thinking hows the foot pump is involved/or hows its wired to be more exact. The factory diagrams leaves these little details out and I hate letting the smoke out of black boxs.

The foot switch is basically in parallel with the wiper switch so that when you hit the foot switch it starts the wipers and the slip ring comes into play. The motor will run until as JJ described it "the open seeking switch is made (or really unmade in this case)" So if you hold your foot on the switch the wipers will run normally, as soon as you release it goes into the same mode as if you had just flicked the wiper switch on and immediately off.

[wrench459]

Does this mean the 18 gauge blue wire from the wiper motor is grounded at washer pump switch or at the speedo brown wire?
This is only a park question not the WW motor case ground.

[P.J. Romano]

Back from a business trip, I continued to look for a fix for my wipers that are not returning to park position. As I never cleaned and re-lubricated wiper motor, I decided that it would be a good time and it would also give me another possibility to find out if that green wire is powered.
When I opened the wiper motor, I found it to be in as new condition. My car originated from San Diego. It appears that in California the windshield wipers are seldom used! Still, I cleaned it and lubricated.
As expected, green wire was dead at the motor. I briefly powered it with a piece of electrical cable straight from the battery - sure enough, the wipers returned to the park position immediately.
At least, I know it is a green wire, most likely lost contact at the wiper switch.
To be continued...