Our 1993 Saab 9000 Aero is having electrical problems: The directional signals and emergency flashers have stopped working. We’ve ordered a flasher relay believing that may be the problem but now find we have no working rear brake lights. Are there ways to troubleshoot the wiring problems?
With the proper wiring diagram, yes.
Question. When you flip the turn signal lever to left or right:
Do the dashboard turn signal indicators illuminate and not blink?
Do the dashboard turn signal indicators not illuminate at all?
As to the brake lights you should use a voltmeter or test light to verify there is power provided to the brake light switch and THROUGH the brake light switch when the pedal is depressed.
Should have added that it’s possible these 2 problems could be related. With age and heat, sometimes the bulb filaments can sag in a dual filament bulb. When this happens and the filaments touch odd things can happen.