I have a 1983 GMC 2500 pickup. The park lights worked and so did the turn signals, but with the park lights on and you turn on the turn signal the left front one would not work nor the right rear. I decided to check with a test light the socket on the front and caused a spark, now the park lights, and turn signals will not work, all of the fuses are ok. Can anyone tell me where to check. Thanks

 

sounds like you probably blew a fuse would be checking the fuses again use your test light to check them turn on the key and turn on the park lamps and make sure you have power at both ends of the fuse. as per your original problem sounds like you was tracking it down up until you shorted it out the turn signal and park lamps are two different circuits and the only thing they have in common is they use the same double filament bulb and share the same ground for both.
if its the turn signals malfunctioning you might check for power going through the turn signal switch should be a connector at the base of the steering column thats easy to get to, if its the park lights would be looking at the bulb and socket and possibly the headlight switch if non are working.