Good morning,

I am finishing installing vintage air in my 68 non-AC car. With everything together, the wipers no longer worked (limited switch pressed down).

Initially, I had power at the limited switch and wiper solenoid under the dash (driver side) after the install. That power has since disappeared.

I ran a new ground to the wiper switch. Power to the solenoid was shortly restored but has since disappeared again. This is directly related to the limit switch which has full continuity; no power at solenoid = no power at limit switch.

When I rapidly flick the wiper switch between all three positions, I do get a voltage reading on the brown wire to the solenoid as high as 5-6 volts.

Also, the wiper switch does change voltage feed to the colored wires at the wiper motor.

Prior to the installation, the wipers did work. I did remove the orange wire running from the block to the old blower. The old blower is ground with the wiper motor and I did reground it (ground for wiper is good).

The old heater controls wires have been removed. The heater controls brown wire is reused for the vintage air power with ignition on. There is an orange wire that was leftover. But the three wires going to the old heater box were removed.

The override switch is inoperable. The one side needs to be grounded. And the second side does not have power.

Any thoughts? I tried looking at old Wilcox info but I cannot find a good link. Wipe motor is new and def has power.

Thank you

 

I was very fortunate as when I bought my 1968 C3 everything was working with the windshield wipers. The problems over the years has been a good source of ground was added to give that part of the dashboard a good solid ground connection.

When my wipers acted up I noticed that it had the 12 Vdc that it needed but the ground was kind of intermittent. I gave it a good solid connection to ground and that is when things worked the very best for my 1968 C3.
The ground I added was directly below the wiper switch and connects to one of the switch's screws so the metal part was grounded. Without the ground and my system was useless. If you need me to I can open up the dash and check my wiper switch. I can also check the large laminated wiring diagram (not quite a schematic) and see what they have to show going on.

One tool that would be very useful for you at this moment would be a tool called a Power Probe as it really helps locating electrical issues. The tip of the tool can provide either 12 Vdc or ground at the tip which can be changed simply rolling a switch on the side of the tool. The power probe can allow you to test the 12 volt components and supply power to a circuit to verify that the motor spins or whatever you are looking for. The tip has a built-in 20 Amp Circuit breaker to protect the tool and the vehicle. I loved this tool so much I have two of them now.

My 1968 Corvette was built almost 58 years ago and there could be a lot of corrosion in the electrical system. The contacts on the light switch were cleaned using a #2 pencil's eraser as it does a great job and is cheap.
I also like to use DeOxIt as it removes the corrosion in one wipe of their liquid on old or dirty contacts. It made a big enough difference that you could see the difference in brightness of bulbs on the cleaned side versus the old side. They sell it on Amazon.

I would imagine that the issue is electrical and not a mechanical failure. What happens when you turn the little **** under the dashboard? The one that stops the wipers immediately when activated. Are all the parts in the right places and working? Are all the wires connected properly?

One of the early things I did after buying the C3 was to have a Corvette shop replace the entire set of Vacuum Hoses. They used quality hoses from DocRebuild and the mechanics ran the hoses just like the original hoses and it was clean and very professional. For the next 20+ years my headlights opened so fast they just popped up. The wiper door and other parts did their job perfectly.

My car is a non A/C C3 as well, it should be a lot like your car in that part.

 

I appreciate the reply. Similar to you, I also added a ground wire to the wiper switch.

the **** under the dash is not function, it’s brown wire has no voltage. Same with the wiper solenoid to the right (towards console).

I am noticing there is no power at the block for the brown wire. However the fuse thst links to it has direct power which is the yellow wire. That yellow wire goes to the relay in center console. From the relay, a light blue wire Carrie’s power to the switch.

Here is a reference of what I’m experiencing :



Second from the left, the 18 brown wire is dead. It goes into the block and attaches to the fuse panel. The yellow wire comes out that fuse and it has power. I do not know where to head from here. I do not understand how that brown wire should receive power.

My only thought would be something to do with the orange wire to the blower. Would removing that wire at the power block disturb power supply to the brown wire for the limit switch.

 

Bench tested motor. Got a few clicks but it’s dead. Fried it during my vintage air install. Probably bad grounds at the switch and override. New motor should work and I redid all grounds.

 

For future readers. A new motor resolved my problem. In summary, the motor was not running therefore it was no longer powering the brown wire coming out of it. Probably messed it up during my vintage air install. I did see a spark at the wiper switch ground when putting in the new vintage air dash vents.