My plan for today was to remove the wiper solenoid from the rear of the tachometer and test the vacuum function. I found that the car had a dead battery. As I was charging the battery, I reached behind the dash and found that the solenoid was warm to the touch. Once I removed the solenoid I discovered that there was power to it with the ignition switch turned off. I then checked the wiper motor wiring and found that there was power to all three wires in the harness that goes to the limit switch and the wiper motor was also warm to the touch. I turned on the ignition and found power to the yellow wire with the wiper switch in the off position. With the ignition on and I move the wiper switch I get a click from the wiper motor. With the limit switch pushed in the wiper motor doesn't run. Could it be that the wiper motor has gone bad and that's why there's power to the wires going to the limit switch with the ignition off?

 

Hi s,
Someone with more 68 experience than I will have to clarify, but I remember that there was a situation with 68 cars having the wiper circuit remain 'hot' when it shouldn't.
I know a change was made but I'm not sure when that occurred or what it was.
Could that be the cause of what you're 'feeling'?
Regards,
Alan

The problem was causing a drain on the battery.

 

Leave the solenoid unplugged and then fully charge the battery. After the battery is fully charged, then ensure you have vacuum(engine running), then plug the solenoid back in..... let the wiper door cycle thru and reclose and then check to see if it still has power to it. I am suspecting that your door did not fully close and that you turned the vehicle off with cycle not complete. Go review the willcox website for wiper door troubleshooting-- it's fantastic.

 

I went through this starting last fall on my 1968. After a bunch of investigating and running around, it came down to essentially a failed seal on my wiper actuator. (well, and a leaky bypass under the dash). See here:
https://www.corvetteforum.com/forums...energized.html

 

The wipers were working before, but the wiper door was not. I found that the solenoid vacuum hose was connected to the filter end and not the connection by the electrical connector. Before when starting the engine the wiper door actuator would open. When I pulled down the override the rod would retract. I knew this was backwards and that’s why I decided to check the solenoid for vacuum via the mighty vac. Today finding the battery dead is a new wrinkle. I just can’t figure out why it has power with the ignition turned off and I’m sure that’s not right. I let the battery charge for over an hour and that’s when I found the wire for the solenoid had power and the wires from the wiper motor also and the wiper motor was actually hot to the touch. I believe the wiper motor is the source of the problem, but I’m just guessing at this point. I’ve looked through old threads and the troubleshooting guides, but haven’t found an answer.

 

the wiper is activated by a signal to the brown wire, there is 3 wires on the wiper motor
when the wiper switch is turned on that powers up the brown wire, maybe the wiper
brown wire is crossed and has constant power.

 

The three wires coming out of the wiper motor that run to the connector in the harness and then to the limit switch all have power when I check them with a test light.

 

the key to the 68 wiper operation is the brown wire correctly wired, 68s don't have
a limit switch at the wiper arm.

 

I’m referring to the switch on the firewall that’s activated by the movement of the wiper door. It seems odd that the wires all have power. The wiper motor was working correctly before and now it’s not. I’m thinking of removing the wiper motor and testing it as per the Willcox videos.

 

OK...I just got done working on a 1968 that had wiper motor issues so this is still fresh in my mind.

I will be referring to the 3 pigtail connector that comes out if the side of your wiper motor at his time....that connects to the main body wiring harness.

The RED wire will always have voltage on it.
The BROWN wire will ONLY get power WHEN the LIGHT BLUE wire gets a GROUND Signal...and when this happens it provided 12 volts to the vacuum solenoid solenoid.

The LIGHT BLUE wire is really important and this wire comes out of the armature housing the control wire in this system. And oddly enough...that light blue wire is connecting to the wires that go to your limit switch on your firewall....which is also getting a ground control from the single wire switch that is mounted under your steering column....that allows you to STOP your wiper motor by turning this switch.

The switch UNDER your steering column is NOT a 12 volt source...but rather a GROUND source. That is where the 1969 wiper system differs. GREATLY

The BROWN wire gets its 12 volts WHEN the light blue wire is grounded....and that BROWN wire then sends a 12 volts current to the solenoid. So ...to get your motor to work....the BROWN wire does not matter...and it only matters IF you want the wiper door and vacuum system to work correctly.

Something that I have found and does not make sense...is that when I look at my wiring diagram....it ONLY SHOWS ONE wire going to the square 3 wire connector that the pigtail connects from the motor connects to...BUT on 3 1968 that I had looked at. I can clearly see 2 wires crimped into the one terminal that goes into that connector. When I tested it...that terminal does have a ground...even if I switch the under steering column OFF...but not as strong of ground...so it seems to not be at full strength...so-to-speak. It makes no sense that I have not yet found where that other wire that is crimped to that terminal that is obviously providing some value of ground. AND on the 3 1968 Corvettes that I looked at....that wire is just like the one I worked on and that terminal was showing to have some ground value to it...but not a full ground.

Now as for the 3 wires in a row connector that plugs into your wiper motor . The center one is going to have 12 volts when the key is ON and the outer terminal each side is what is providing a ground signal in order to make the wiper motor go in PARK or LOW speed or HIGH speed.....and these grounds are controlled by your wiper switch.

MAKE sure your wiper motor is GROUNDED...and the wiper motor is gettign its ground by that single BLACK wire that plugs into the terminal that is screwed onto the front cover area of your wiper motor.

I believe I am 100% accurate in what I wrote....due to having a detailed, extensive phone conversation with the guy who restores the wiper motors for me.

IF I am incorrect...then where ever I made a mistake(s)...correct it.

I believe Willcox has a tech article on this specific issue.

DUB

 

I tried to unplug the wiper motor and this is what came with the plug. Looks like I’ll be looking for a replacement.

 

I agree...there is a problem that might be able to be repaired on your work bench...and then again ...might not.

DUB

 

Sullyman..

If you broke the resistor, I've got a replacement that works just fine.

https://willcoxcorvette.com/wiper-mo...82-replacement

There is a ton of info on my tech site for the 1968 wiper motors including videos.. Plus this tread... You get stuck, email me back at service@willcoxcorvette.com


Wiper Motor Bench Test 68 Ver 1


Wiper Motor Bench Test 68 Ver 2 "Follow up"


Great threads on 68 Wiper motors can be found here:

Mister Willcox, 68 wiper motor

68 wiper problems

Upload this.. It is 100 percent correct and to my knowledge is the only 100 percent correct schematic for the 1968 cars.

http://repairs.willcoxcorvette.com/1...ess-schematic/

And use this search for all other things related to 68 wiper motor issues.

http://repairs.willcoxcorvette.com/?yt=1968&s=wiper

Willcox

 

Thanks, I ordered a new one this afternoon via your website.

 

Today I received the new wiper motor. I installed it and no change. It even started smoking a little so I unplugged it. I’ve checked everything I can think of. The relay is working and I unplugged the override switch just to eliminate that being a possibility. When I connect the battery I have power on the red wire coming out of the harness. With the key on I had power on the red and brown wire. The odd thing is that with the key off and I connect the plug from the wiper motor to the harness I have power on all three wires when I just checked it and noted power only on the red wire. What am I missing?

 

You MUST use Willcox's tech advice and bench test again.

What I know about it I wrote it out in POST#10.

You also have to be very precise when you are describing what you find when you plug connectors together. Only beacsue I am trying to help...

Knowing that on this wiper motor there are 2 three wire connectors. One is flat with the three terminals in a row that actually plug into the wiper motor.....and the other is the square one that is attached to a pig tail coming off of the wiper motor. You have make it perfectly clear on which one you are dealing with and what happens.

For what it is worth....I recently installed a new wiper motor for a 1968 and it worked 15 times perfectly....and then ...it stopped. I tapped on it it and it began working again and that was AFTER I had verified ALL of the wires were doing what they needed to do. Mine did not smoke...the old one did...but not the new one.....so...bench test it or get a hold of Willcox and talk with them.

DUB

 

Sorry for not being clear as to what I was referring to. The three wire plug that I was referring to is the square plug. When I connect the battery I have power on the red wire in the square plug coming from the wire harness near the limit switch. This happens with the key off. I don’t know if this is normal or not. When I turn the key on and slide the wiper switch to the low speed position the relay clicks and I had power in the same plug on the red and brown wire. So far that seems correct. I shut off the wiper switch and the ignition. I plug the square plug from the wiper motor into the female connector and checked it with my test light. This is when I see that I don’t have power only on the red wire, but on all three. This doesn’t seem correct. While doing the preceding I had disconnected the override switch just to eliminate that as a potential problem. Prior to this the wipers were working.

 

The BLACK wire that is on the square 3 wire connector is GROUND and should NOT have power on it. The BLACK wire in this connector joins to the pigtail of your motor and will be a light blue.

Read post 10. I comment on what you should expect for the red wire and so on

IF the black wire/blue wire has power on it...something is wrong for sure.

DUB

 

I agree that something is wrong. With the square connector unplugged and I check with a test light I am getting power on the red wire only. This is with the key off. When I plug the square connector to the female counterpart on the wiper motor I am seeing power on all three wires. The black, red and light blue. This is with the ignition off. Should the red wire in the square connector from the harness have power with the key off?

 

You asked again.

Should the red wire in the square connector from the harness have power with the key off?

And my reply again....Read post 10...third paragraph or sentence.

DUB