The are three problems that may disable your turn signal on a classic mustang; the bulbs could be out, the signal relay could be bad or the turn signal switch in the steering column could need replacing. To see how to replace a turn signal switch visit this web address http://averagejoerestoration.com/how-to/how-to-install-a-mustang-turn-signal-switch/ ::AverageJorResto.com::
The common reason why is a fuse blew.
you have a bad turn signal flasher.
If the turn signals and emergency signals don't workout sounds like an electrical problem's would suggest that you take it into the closest shop to get the problem diagnosed properly.
its either the flasher or the turn signal switch
Check fuse Check bulbs--they are double filamented with the smaller for turn signals Replace turn signal flasher--Most common problem
this car may have separate flashers for the turn signals and the emergency flashers
If the 4 Ways/Hazards are disconnected then neither will work the park lights nor the turn signals.
It could be the turn signal bulbs, some vehicles use separate bulbs for the hazard and turn signals. It could also be a bad switch or wires for the turn signals.
Both fuses # 13 and # 18 are 15 amp fuses for the electronic flashers ( it doesn't show which is the hazards and which is for the turn signals )
The 1990 VW Jetta turn signals will not work when the ground wire is broken or corroded. The turn signals may need the lightbulb's replaced.
Either check the fuses or change the bulb.
In pa you dont need turn signals