Wiper/Horn fuse blows. Common trouble spot...? '69 Beetle

[radbug69]

The recently recommissioned '69 Type 1 has been doing great although it developed a situation where using the wipers blows the fuse. In that the fuse is also the horn fuse and that does not cause a fuse failure when used, I should conclude that the one of the wiper components must be the issue.

I'll start poking around but wondered if any of you knows of a specific area that may have been documented as a trouble spot or short on say, the motor or some other area...?

As a side note, we don't use the car intentionally in rain however, it would be nice to be able to use the wipers if we do encounter rain.

As always, thanks,
Rob

[OldSchoolVW's]

[ashman40]

I have a suggestion for troubleshooting... remove the wiper switch from the dash and test if the wipers work normally with the switch not installed in the dash. The switch does ground thru its mount to the dash and this means the wiper arms may not park properly while you are holding the switch in your hand (wear gloves), but if the fuse does not blow it indicates the switch is internally grounding one of the circuits to the case of the switch and blowing the fuse.
This is a common problem when the switch backing plate starts to come apart and the internals of the switch can move around. Tightening the backing back down (cable tie) or replacing the switch usually works.
_________________
AshMan40
---------------------------
'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!}

[radbug69]

Ok, so I have spent a bunch of time trying to figure out what is going on with the wipers..

Just to do it, I flipped the wipers up and away from the windshield to test the operation of the wipers and low and behold that did not blow a fuse. Odd.

Flipping the wipers back down to the screen and the fuse blows. That led me to think that the drag on the wiper against the screen was the issue.

A second attempt to test had the wiper continue to low a fuse regardless of whether they were against the screen or not.


Next,
I pulled the obstructions away from the back side of the dash to hopefully get at the switch... Man that is a task.

I have yet to be able to remove the switch to discern whether it works without blowing a fuse or not.

I did encounter this small connector wire (smaller than a conventional 1/4" terminal) that seems to be connected to the green wire of the switch...!

To make things more confusing, the wiring diagrams that I have looked at (from the tech section here) do not indicate that there is a black wire with a small connector or where one might go...

This is an August '68 built 1969 Model #119 121 994

I have checked all of the diagrams that might be germane to this car...

Uggg.

Thanks,
Rob

[radbug69]

[sb001]

[radbug69]

[ashman40]

[sb001]

[ashman40]

Sorry sb001, that question was directed to the OP. I agree with your assessment that maybe someone has been swapping/replacing wires.

I could be convinced that VW swapped wire colors late in the ‘69 model year, but the OP’s car is a very early ‘69. I’d expect it to be nearly the same as a ‘68.

My suspicions are the wiring harness was replaced at some point and the wiper motor/switch was miswired? Its only a suspicion.
_________________
AshMan40
---------------------------
'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!}

[radbug69]

[ashman40]

There is some troubleshooting you may be able to do without pulling the wiper switch out from the dash...

The following diagram from Speedy Jim's site shows how the wiper switch+motor are wired.

Take a pic of your wiper motor and how it is wired so you can restore the wiring when done. Post that pic here.

Disconnect all the wires at the wiper motor and disconnect the wiper power wire from the fuse box. This will isolate the wiper switch. The switch is still mounted to the dash but you should have disconnected the far end of all the wires coming off the wiper switch. The switch is not connected to anything except being mounted/connected to ground.

Place an ohm meter or continuity tester between the loose end of the green power wire and a good ground point. With the switch OFF there should be infinite resistance between the green wire and ground (make sure the small black wire connector is not touching anything). Make sure none of the wires that were connected to the wiper motor are touching anything (place them on a rag).

Move the wiper switch to each of its ON positions and confirm the green wire is still not shorted to ground. Since all the wiper switch wires are disconnected and loose. if the green wire shows low or zero resistance to ground in any ON position it means the switch is grounding the circuit to the dash.

Test each of the paths thru the switch to make sure it works as the above diagram suggests. This is a positive test to make sure the switch closes the paths as designed.
Also do a negative test... make sure each terminal is NOT connected to the other terminals and not connected to the case of the switch when in each position.


Move to the wiper motor. Test each of its terminals for resistance to ground.
Terminals 53 and 53b will have a path to ground thru the motor. There should be some resistance thru these paths and they should be different between the two as they are different circuits. It should not be zero (I think?). If you find zero resistance down one of these paths it could be an internal short inside the motor.
In the parked position, there should be zero resistance between 53 and 31b.
When not parked there should be zero resistance between 53 and 53a.
Make sure 53a and 31b are not shorted to the body of the motor.

Try these tests and report what you find.
_________________
AshMan40
---------------------------
'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!}

[sb001]