Fuses Blowing

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Fuses Blowing

Post by Joey21 » Thu Sep 14, 2017 11:52 pm

I've been working on this for a few days and am stuck. I have a 1966 bug with a 12V conversion. The wiper switch is a 1967 and the motor is a 1966. I have checked the voltage and grounding and all seems good, however I cannot even install a fuse (power on or not) in the terminal where I connect the wiper switch and it pops.... Any ideas? I was thinking installing an inline resistor?

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Re: Fuses Blowing

Post by sideshow » Fri Sep 15, 2017 8:11 pm

Wait a minute (I'm not a beetle person) but are you trying to use a 2-speed self parking wiper switch with a one speed no-parking wiper motor?

I would back track to the DIN numbers on both sides and see if that is even possible.

And yes doubling the input voltage to a wiper causes all sorts of issues, usually leading in failure. The resistor is a cheap solution that works.
Yeah some may call it overkill, but you can't have too much overkill.

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Re: Fuses Blowing

Post by Marc » Sun Sep 17, 2017 6:44 am

Yes, you can use a two-speed switch on a one-speed motor. VW obsoleted the old push-pull switch in favor of the `67-style twist-on unit decades ago. Either just use one of the "on" positions or add a jumper wire between them.

The dropping resistor is the easy-sleazy way; as it heats up its resistance changes, as does the wiper speed, and it can get HOT so must be located where there's no chance of a piece of paper or cardboard in the trunk ever falling onto it. There are adjustable resistors available for fine-tuning the speed, but a 4Ω fixed is usually pretty close. Needs to be a "power" resistor (usually wire-wound construction) rated at 50W or more.

You can also get a 12V armature that'll go directly in place of the one in the one-speed 6V motor (if it's the more-common SWF motor, not the Bosch-made one). Still one speed, but an improvement over using a resistor. http://www2.cip1.com/ProductDetails.asp ... %2D811%2DB

The best solution is to update to a 12V 2-speed motor. One from a `67 goes right in, using the `65/`66 connecting link. The `68/`69 motors are almost identical to the `67 but have a larger pivot pin on the bellcrank, so you either take the transmission section apart and replace that with the small-pin one or make a link with a large bushing at one end.

You can also use the entire assembly from a `68/`69, where all the pins & bushings are the larger size. Arguably the worst years for Beetle wiper linkage VW ever had, especially susceptible to going "over-center" and locking up when the pivots get sloppy since they stopped using the "tail" at the end of the crosslink which prevented that on earlier models, so replace the pivots if they're worn.

In `70 they went to bolt-on wiper arms and beefier, serviceable larger-diameter shafts, with bigger holes through the cowl and a different mounting tab for the new, more powerful round motor. A `70-up assembly can be grafted in without enlarging the holes by simply slicing the rubber grommets apart and cutting out the old-style mounting bale (so the whole thing is just suspended by the cowl and shafts). The park circuit on `72-up motors (the ones with a pigtail harness rather than a row of male spade terminals) is different and incompatible with pre`72 dash-mounted switches, so the motor needs to be from a `70/`71 Standard or a `71 Super. Because of the need to cut (or bend the bejeesus out of) the support bale this wouldn't be the best way to go for a car that might be restored to original some day; you can still have the benefits of the beefier shafts and bolt-on arms by fitting `70-up shafts to a pre`70 frame and motor, though.

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