A year ago I rebuilt my wiper unit, and took that switch apart. What a mess, I remember. I couldn't remeber which contact went where. the top and bottom contact are similar, and one of the wafer spacers is thicker than the rest. I searched for these pics, or a working switch, with no luck. My FSM didn't have decent pics either. A little trial-and-error, a few blown fuses, and I got it back working correctly. Glad something finally got posted. Thanks, IDave.
Wipers intermittently fail to "home".
- Thread starter Brian in Oregon
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Okay, I'm bringing this back up. I tore into my wiper motor the other day, and I'm stumped. I'm hoping IDave or someone could tell me how the electrical "park" function of this works. From the pics that IDave posted, everything is where it should be. My problem is that the wipers do not "home". When I turn off the switch (i.e. push it in), the wipers stop no matter where they are. I checked the power at the plug by the motor and 3 of the 4 wires have power to them when the switch is on in any position (hi or low). Is this right?
Basically, my question is, electrically speaking, what happens? Is the ground interrupted and that shuts off the wipers when the ball raises? If I get this figured out, then I can start backtracking to see what is going on. As you can see, I'm no electrician, so it is trial and error for me.
Thanks for any help.
Basically, my question is, electrically speaking, what happens? Is the ground interrupted and that shuts off the wipers when the ball raises? If I get this figured out, then I can start backtracking to see what is going on. As you can see, I'm no electrician, so it is trial and error for me.
Thanks for any help.
Edit: I looked again. There's a substantial difference between the way the two motor system (early 1960s) and the one motor system are set up. I looked some more and used a test light and found out a bit more info. Sorry if I confused anyone tonight.
So:
The HOT wire to the motor is the solid blue (L) wire which comes directly from the Switched side of the fuse box. It connects to one brush, and has a jumper wire to the top blade on the 3 blade switch on the motor. It is always hot while the ignition is on.
The motor is grounded ultimately via the dash switch. It is ALSO grounded via the windshield frame.
The LR and LW wires are connected to two separate brushes (so there are 3 brushes total).
When the ball rises up, and the top blade is touched by the middle blade, the LB wire becomes hot. This is true in both ON positions for the dash switch as well as when the dash switch is off.
In the off position of the dash switch, ALL wires will be hot to a circuit tester.
In the low position and the high position of the dash switch one or the other of the LR and LW wires will be hot, but not both.
Someone who understands motors better than I can explain why this works and what happens at the dash switch, which I haven't pulled apart. Unfortunately, my wiring harness doesn't match the wiring diagram, so I can't give better detail.
So:
The HOT wire to the motor is the solid blue (L) wire which comes directly from the Switched side of the fuse box. It connects to one brush, and has a jumper wire to the top blade on the 3 blade switch on the motor. It is always hot while the ignition is on.
The motor is grounded ultimately via the dash switch. It is ALSO grounded via the windshield frame.
The LR and LW wires are connected to two separate brushes (so there are 3 brushes total).
When the ball rises up, and the top blade is touched by the middle blade, the LB wire becomes hot. This is true in both ON positions for the dash switch as well as when the dash switch is off.
In the off position of the dash switch, ALL wires will be hot to a circuit tester.
In the low position and the high position of the dash switch one or the other of the LR and LW wires will be hot, but not both.
Someone who understands motors better than I can explain why this works and what happens at the dash switch, which I haven't pulled apart. Unfortunately, my wiring harness doesn't match the wiring diagram, so I can't give better detail.
Last edited:
This a good reference here, excellent pics and descriptions. FAQ worthy for sure.
My highjack (not having been in the wiperbox or checking the swtich), the wipers (1978) return to the lower portion of the windshield when turned off, but not the whole way to the bottom of the windshield. I can get them to stop the whole way at the bottom if I fitget with the switch a little. Any ideas?
My highjack (not having been in the wiperbox or checking the swtich), the wipers (1978) return to the lower portion of the windshield when turned off, but not the whole way to the bottom of the windshield. I can get them to stop the whole way at the bottom if I fitget with the switch a little. Any ideas?
Thanks IDave. This gives me some ideas. Back to the garage!
So when they start from the too-high stopped position they first go down a little, then back up?
Mine had a similar issue and I just took off the arms and rotated them on the splines, but you wouldn't want them to go down and touch the paint.
I edited my note above to reflect better research into my working wiper. We keep learning. 
I was thinking wiperarm placement too, but the arms move properly within the range they are supposed to just not stopping fully at the bottom. go figure...
1Fine40
Rust Buster
On the later wipers (lower mounted ones..) there appears to be two things happening that can cause this problem. 1st is wear of the small copper finger stock that carries current to the motor. As it wears down, it makes contact with the conductive surface in the gear case at progressively different points. This makes the point of contact/no contact change, which makes the motor rotate more or less before stopping. The second thing is the "pre-load" on the motor worm gear. If it is loose and sloppy, the wipers will park intermittently in slightly different spots. If you tighten up the preload screw a touch(not too much..) it can restore the parking spot to be right on again IF the copper contactor is not worn down...I don't have a picture, but will take some when I replace my linkage arms soon. I know this makes no sense at all unless it is sitting on the bench in front of you..
Cheers!
Cheers!
I have to old school double motor on my 67' very randomly my passenger side clicks on and then off. Just going down the road and it wipes. It's very strange but I think it is a short between the three contacts on the motor itself. Also my drivers side returns while my passenger side stops when i turn the switch off. Timing is everything.
Wiper stop cover
This is a great thread and should be added to the FAQ!
Does anyone know where to find one of the little black covers? Mine had one when I bought it. Took it to the local shop to get new tires, working exhaust welded on, oil and lube job, as well as safety and emissions. When I got it back I noticed the little cover was missing.
Haven't looked too hard but this doesn't seem to be an easy to find item.
This is a great thread and should be added to the FAQ!
Does anyone know where to find one of the little black covers? Mine had one when I bought it. Took it to the local shop to get new tires, working exhaust welded on, oil and lube job, as well as safety and emissions. When I got it back I noticed the little cover was missing.
Haven't looked too hard but this doesn't seem to be an easy to find item.
Someone said that the frame needs to be grounded, and this is true. Several years ago my wipers were not working properly and after replacing the motor and the dash switch, I realized that the frame was not getting a good ground. I ran a ground wire from under the dash, up the windshield frame and terminated it on the wiper motor housing. No more electrical issues with the windshield wipers.
BTW, I have a 74 with motor at the top of the frame.
James
BTW, I have a 74 with motor at the top of the frame.
James
PabloCruise
SILVER Star
1Fine40
Rust Buster
Sorry, I did not get any pics of this when I repaired it...my bad. I do remember that you can remove the wiper motor assembly, then you will see a small screw head with a locknut on it. That is what takes up the play on the wiper motor shaft. I'd try that first...it helped a lot on mine. When I snugged it down a touch, the blades parked inthe same spot each time, but it was not the right spot. The I opened up the case to find worn finger stock...fixed that problem with some thin copper strips and solder...
Again, I apologize that I didn't snap a pic...
Cheers
Again, I apologize that I didn't snap a pic...
Cheers
PabloCruise
SILVER Star
I had similar symptoms where my wipers would not stop after shutting off the switch. They worked fine previously -- parking at the top when the switch turned off, but then one day they started running continuously until turning off the key (at which point they would park in the right spot). Studying the pictures and info from IDave, I was able to fix my issue by simply running a piece of 1000 grit sand paper between each of the contacts on the three blades (between lower and mid; and mid & upper). After that, they worked like a charm.
Thanks to IDave and others for the detailed pics and information.
Thanks to IDave and others for the detailed pics and information.
PabloCruise
SILVER Star
Any recommendations as to what is a good grease to use in here when rebuilding?
The original grease gets hard and viscous in the cold temps...
The original grease gets hard and viscous in the cold temps...
Probably a synthetic like dielectric grease. Just a guess.
I use Syl-Glyde from Napa on gears like that. Non-conductive so it won't short stuff out , doesn't harden or create issues. The stuff in the tubes is used for mostly rubber parts around here - radiator/heater hoses and such so they don't weld themselves to the tubes. The spray can is used on gaskets so they don't weld themselves to parts that can be damaged by scraping. Never had a leak yet and stuff actually comes apart . The aerosol can works great on door and trunk seals so they don't freeze to auto bodies. I'd use the stuff on the wife, if she'd hold still....
NAPA AUTO PARTS
Sarge
NAPA AUTO PARTS
Sarge
