Some of the symptoms of ignition switch problems are things that don’t work or are intermittent like radio, turn signals, wipers or heater.
There was a FREE recall on Ford ignition switches. They overheat and sometimes catch fire. That burns up the steering column and sometimes the car interior. Since this is very old information, you may not be able to get the switch replaced for free anymore. The auto parts stores sell the switches for $13-$15.
Saleen0679 was nice enough to dig this up for us awhile back:
Replace a 1979-1993 Ignition Switch Assembly
Free FORD OEM wiring Diagrams
PM me your email address and I will send you a complete Ford Factory 89 Mustang electrical diagram set. The zip file is 2.5 MB and is too big to fit through Stangnet's email gateway.
89 Mustang wiring diagrams zip package–
They are in a zip file format to reduce the size of the package. You’ll need WinZip or other Windows archive tool to extract them from the zip file. See
www.majorgeeks.com - Download Freeware and Shareware Computer Utilities for a free download.
You will need the Adobe Acrobat viewer which is also a free download –
www.adobe.com/products/acrobat/readstep2.html - Adobe Reader download - All versions