My wipers are possessed

[02Pilot]

I could use some advice, or in lieu of that, recommendations for a good exorcist in the NY metro area.

 

Driving home tonight, my wipers decided to come on (low speed) whenever they felt like it. It seemed that accelerating or going up hill triggered them on, so I'm figuring there's a short somewhere. When I got home, I grabbed the harness at the motor back to the fuse box and jiggled vigorously, but no action, so it would seem the switch is the next place to check. Anyone ever encountered this one? Any other ideas about what or where to check? Car is a 1974.

[Mike Self]

If yours was a 72 or 73, I'd suspect the wiper on-off switch, but squarelights don't have that problem (different switch).

 

So it sounds like the problem is in the self parking (no relation) system.  Your wiper motor has two power sources; one via the switch and the other via the self parking mechanism.  If the latter goes on the fritz, the wipers will continue to run, regardless of switch position, so long as the ignition is on.  The mechanism is inside the little tuna fish can part of the wiper motor.  

 

I wrote a column on troubleshooting and repairing perpetual motion wiper motors; PM me if you'd like a copy.

 

mike

[02Pilot]

PM'd you, Mike.

[John76]

2 hours ago, 02Pilot said:

Any other ideas about what or where to check?

Check the plug from the wiper motor through the bulkhead.

This is susceptible to water and dirt in the plenum.

Also check the brown ground wires to the chassis near the brake fluid reservoir. The wiper ground is shared with the brake fluid level sensor and the brake pressure balance switch (if fitted).

 

Here's a sketch of the wiper parts to troubleshoot. 

 

 

[2002iii]

Try jiggling the wiper arm switch on the  steering column and the connectors on the backside of the switch.

[02Pilot]

Thanks, folks. I'll try to dig into it later today (if not, then tomorrow) and see what I can find. Stay tuned.

[TobyB]

+1 for Mike on the parking circuit inside the gear housing on the motor itself.

 

t

[02Pilot]

I pulled the motor and took it apart. No obvious smoking gun: all three brass contact arms were intact and in place, the disc looked clean, all the wires were still attached. The grease was unsurprisingly lumpy, so I scraped it out, regreased with Super Lube, and jammed it all back together. The only thing I did spot was a janky crimp splice in the brown/red wire about halfway along the pigtail; I fixed it, but that wire doesn't seem to be a factor if I'm understanding the diagram. I'll have to drive it and see if the problem persists.

[TobyB]

The other thing to check if they're not parking are all the grounds-

the park circuit has to ground the armature to brake it quickly, so if it's

not getting ground, it will usually over-run the park position...

 

...it's been a looooonnnnggggg time since I've messed with one of these...

 

t