wigwag headlights?

[FoxBodyNut]

Just curious if anybody knows of a wigwag headlight module that will work with a 1990 Mustang SSP?, saw some on Galls site, but it says 1992-2011, how would a 1990 mustang be different than a 1992?

http://www.galls.com/uniformstyle?as...og&style=FS039

[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.