[unclescratch]

Vehicle is a 1965 GTO w/2-speed wipers w/washer. Everything works well (low and high speed and washer) except the wiper motor will not park, it just stops wherever you turn-off the dash switch. It worked fine one year ago.

For diagnostics I am using (an original) 1964 Pontiac Tempest Chassis shop manual. It is excellent!

I have drilled-out the rivets and removed the gear box cover. The (original) grease is still very pliable. The output gear opens and closes the contacts of the park switch, which opens and closes the continuity between terminal #1 (red wire into motor housing) and the housing.

I would like to inspect the contact points of the park switch, however I am uncertain how to separate the output gear and shaft from the 4-lobe cam that runs the washer. Therefore I can't get any inspection of the condition of the contact points.


What to do????

[Old Goat 67]

Try grounding the motor housing good first. A clip lead is easiest for this test.

[unclescratch]

I have attached a ground from the housing to the 12v source (a marine battery on the bench). The stop switch does loose continuity fine when the cam comes around on the output gear.

I used a battery terminal puller as a gear puller to remove the 4-lobe cam successfully. The contact points still had a good accumulation of grease that I was able to see and now have everything cleaned up nicely w/carb cleaner. The points have worn themselves into a good fit, not necessarily perpendicular to their arm, but with good contact and they are nice and clean.

The re-test was no different, still no park with the motor running @ slow speed.

[unclescratch]

Must pay closer attention at teardown. I had placed both washers on the output gear shaft 'outside' of the gear cover. I found that I needed to install the fatter of the two inside the gear cover to lower the output gear down enough for the cam to engage the shut-off switch.

Looking back, there had been quite a lot of grease installed 'way back when' on the various gears. Its been a pretty hot summer here, and a glob of that grease collected onto the cam follower of the shut-off switch. Having cleaned-up everything, and got the cam and follower to become re-acquainted, I now have 'park'.

[64speed]

I literally worked on my wipers for two months before I got them to work properly. I went thru bad motors, bad switches, and transmission linkage that would bind up or fall apart. I finally was able to get them to work but in retrospect I wish I had bought the DSE variable speed kit and been done with it

[Old Goat 67]