Electrical/Wiper Problem

Hello, FABO,

The windshield wipers on my '67 Barracuda have always seemed slow (at least in comparison to more modern cars), but today I noticed that they speed up when I turn the heater blower motor off. I have been troubleshooting the wipers for some time now (checking wiring, grounds, etc) but I can't seem to get the wipers right. Is this a voltage regulator problem?

Thanks for any help you can provide.

BlindSquirrel