Trying to troubleshoot a wiper motor problem on my 66, and I'm getting stuck. Need help...

- Everything is new...motor, harnesses, wiper switch, ignition switch, everything.
- I get 12V to the brown wire at the motor when the ignition is in accessory or on positions.
- I checked for grounding of the terminals at the wiper switch for every combination of ignition & wiper switch positions. It's a complicated table, but what I found at the end of it all is that in the off position, the wiper switch housing grounds just fine, but in both the accessory and on positions, I get no ground.
- I believe the switch housing grounds through the gauge bezel; so I'm thoroughly confused about how the ignition switch position could have any effect on that???

One other note...when ignition is in Accessory or On position and I turn the wiper switch to low speed, I hear a click at the motor. There's no attempt by the motor to move, though. Another troubleshooting guide I found says that this is due to a bad ground from the motor case to chassis, but I checked that with a meter, and the ground is good.

Lastly, the terminal on the motor for the yellow wire shows to be grounded while the other two are not. Also, at the switch, I get 12V on the light blue wire but only .04-.05V on the yellow with everything turned on. Could this be telling me that there is an internal short in the wiper motor, and yellow is affected?

Does any of this make sense, and has someone seen this situation before?

Thanks.

 

Nobody gives the year of the car anymore.

 

66, but I believe all C2s are the same.

 

I have had similar wiper issues. Again even though your meter reads ground as satisfactory I would run a separate ground wire and ground it to the frame from the grd. connection on the motor to see if this small change will make the motor operate.

Check out this video from Wilcox on wiper motor testing:
https://www.corvetteforum.com/forums...ing-video.html

Wayne

 

It doesn't. The wiper switch grounds to the cluster gauge bezel, and the bezel has its own black ground wire from the dash harness that plugs on a male spade terminal adjacent to the tachometer. The ignition switch isn't involved in the wiper ground circuits.

 

They are, but this is C1/C2 forum.

 

There is also a black ground wire from the wiper motor that goes over to a spade lug in the heater box and then down to the mounting bolt on the starter. You have to have both grounds. Does your heater fan blow?

 

Running Vintage Air system; so the ground for the heater fan isn't connected, but the ring lug at the end is connected to the starter mounting bolt. It's one continuous circuit; so it shouldn't matter. Plus, I'm getting a good ground from the motor case to the chassis already.

 

I may be wrong but in your post #1 last paragraph you state the yellow is grounded and the other two are not.

Someone correct me here but I think it's just the opposite. The two are grounds and only one is 12V power.

 

It's designed so the center terminal (brown) gets 12V from the ignition circuit, and the two outside terminals (yellow and light blue) ground through the switch, telling the motor to run at either high or low speed. On my (new) motor, the rear-most terminal (yellow) give me a ground to the case. I think a short in the motor related to this is the problem, but looking for confirmation.

 

I would pull the switch out and test the motor as per the diagram below. This will bypass the wiring in the car.

.

 

Where the picture above says "turn signal switch", substitute "wiper switch".

 

Okay, finally got back on this today and determined that the problem is definitely in the motor itself. (Again...really POd about that since I just bought the damned thing from a guy who now isn't answering his messages.) So, I got it out of the car and opened it up. Right away, I could see that it's no wonder the terminal for yellow is gong straight to ground. That's exactly how it's wired...which has to be wrong.





The following link goes to a good wiper motor testing video that shows how it should work. The way mine is wired, it would never work like the one in the video; so it makes me wonder if the guy who built it just didn't know what he was doing, or if it's set up for some other application.

https://willcoxcorvette.com/wiper-mo...ilt-63-67.html

Anyway, I guess none of that matters. What I really need to know from anyone out there who knows how to properly wire one of these is whether I can switch a couple of wires in mine and make it work or if this thing is hopeless, and I need a new motor?

 

Wiring looks to be correct. The clicking noise you hear is the relay, so that part is functioning, but the motor should spin. The test below will let you hook power directly to the motor, bypassing the switch. The guy who rebuilt it must have bench tested it before he sold it to you. It should work. If you get power to it and it doesn't run, take the lever with the short yellow sleeve on the end and move it manually. The motor might be stuck off of the park position.



.

 

Yeah, I put power on it with the washer pump removed and tried everything possible. The only thing left that it could be is the motor burned out. I've already boxed it up and shipped it out to Steve Hackel to get it going again. So frustrating...

 

Here is the test video for the motor and the second link is the help page with a schematic.



http://repairs.willcoxcorvette.com/w...tor-wiring.pdf <-- Help page

 

I read that you've boxed it up already, but......

If it hasn't gone out yet, just a thought.....

Has the unit been stored for a while? I have had rebuilt motors that were stored for a while do this. What happens is that the armature commutator sticks to the brushes. This acts like a seized motor and may be a similar symptom to yours. It's from non use.

In 2 separate cases, both rebuilt but stored for months, one on a C1 motor and one on a C2 motor, I was able to free the armature by just turning the armature shaft gear slightly to free it up. Once unlocked, they both ran fine.

It may be worth a try.

 

Steve Hackel = "The Man"!

I put my motor in the mail last Friday afternoon, and it was at my house today, just 6 calendar days later, including transit time both ways. Not only was he fast, but although I asked for just a mechanical repair and not cosmetics (since it already looked fine), he did the whole thing to NCRS judging standard and only charged me for the mechanical work. On top of all that, he sent it back without even being paid, including the bill so I could send him a check afterward. Additionally, Steve wrote a two page letter explaining what he found wrong in the motor (multiple items) and how there are a few other guys around the country doing cheap rebuilds that don't know what they're doing. [Beware of "boulderkid" on eBay.) The guy could tell exactly who had messed my motor up by what he found inside...he's like a forensic pathologist for electrical motors.

Long story short...it isn't often that I get more than I asked for and pay less than I expected. I really have to thank Steve and recommend him. He does headlight motors ad other various electrical motors, too.

Steve Hackel
15000 South Knox Avenue
Midlothian, IL 60445
708-687-4183