Jason,

While your problem can be a frayed wire. 
It's most likely either the shafts where it passes thru the body (under the arms) are dirty, corroded & binding or you have an issue in the gearbox (which is a sealed unit and shouldn't need servicing. 
Problem is both require removal of the dash to service, as does the front blower. 

If this is going to be a little later in the future, I'd recommend this Glass rain shield product.
I've tried many on the market (and all but this are still on my shelf of disappointed products)
"NO TOUCH RAIN SHIELD" it's pricier than similar products but it easily lasts longer between applications as well. I rarely have to use my wipers, usually only on the delay setting, and I haven't had washers on my van in the 8yrs I've driven it. 
I don't make any money from the product, but I certainly do endorse it. 
I buy it 4cans at a time from the ACE online store 

Best of luck, 
Dan from SYRacuse

Date:    Thu, 13 Oct 2011 23:36:39 -0400
From:    Jason Orr < >
Subject: 1983 Vanagon GL

I am having a problem with my windshield wipers. At first they worked then
every now and then they would go kind of slow. Then one day I needed them
and they didnt work and it blew the fuse for the wipers. Soon after that I
could put a new fuse in the slot and turn the ignition on and within a few
seconds it would blow the fuse. Does anyone have an idea what is going on?
I was thinking it is either the wiper motor or the switch, but I really
dont know. Any help would be greatly appreciated. After I fix this I get to
tackle putting a front blower motor in  8)