wigwag headlights?

[GSPI]

I think it has something to do with the grounded switch headlights. I cannot remember the transition year for the positive and negative grounded headlamp setup so if someone knows that might answer the question fully. Those wig-wags are designed to allow regular lamp operation too so it's critical that you have the correct wig-wag design so that it doesn't burn anything up or destroy the wig-wag device too.