BoatRDavid

It could be cause by a corroded light socket. Remove each signal bulb and check/clean each socket. Also, it could be a bad flasher relay.

My 1998 GMC Sierra, C1500, has two fog lights set in a panel (skirt?) under the front bumper. They aren't working and I haven't done any reach on them. I don't know if the panel was a factory option or after market. This truck has other after market items such as having no tool box under the back (jump) seat, but instead there is a cover (that doesn't open) under which are large speakers. There are two large amps mounted on the back firewall behind the seat back. None of the audio equipment is working.