Choptop is correct. I also had this very same problem on my 68. The cast zinc body of the switch is the path-connection to ground.
Most likely the problem is in fact the switch.
Option A) Spend money and get new switch.
Option B) DIY, remove switch from dash, Put the switch in a vice, very carefully, use hammer & drift punch to open up the factory crimps in the zinc case. The internals will pop out so be ready. Make Notes [img]graemlins/clonk.gif[/img] on orientation and part stack. You will most likely find dried up white lube and carbon tracks. Clean with Alcohol and burnish all copper contacts with 400 grit sandpaper, re-lube with fresh grease. Restack and assemble. Repunch the existing crimps in the zinc case to hold internals. Test with a meter. Re-install into dash. Check your wiper operation and Crack a cold one. Victory! You have done it yourself- and saved CASH!
1968 SS/RS 396/325 TH400 LOS
1968 Z28 302/290 M21 LOS
1969 SS/RS 350/300 TH350 LOS Pace Car