When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I read this link for modifying the front side marker lights to also work as turn signals. The wiring schematic was pretty generic so here it is as it applies to a Ranger.:
Left Turn Signal: Attach a jumper wire to the Light Green/White wire on the left turn signal and run it to the Left Side Marker. At the Left Side Marker, cut the black wire and attach the jumper wire to the black wire running to the marker light.
Right Turn Signal: Do the same as the Left Turn Signal but attach the jumper wire to the White/Light Blue wire.
My Ranger is an '03. If you're unsure of your truck's wiring or how get at the wiring to modify it, invest in a Chilton's or Haynes book first.