Scott,
Thanks for the welcome. I've been eavesdropping on you guys for a while but haven't posted. I'm the original owner of my '91-plus, but for the last 10 years it has been my daily driver, and as such I had to keep it in running condition. I've done lots of mods, as you can see by my...
The 89-91 JBL head units with the up/down "flipper"-style volume control have electrolytic capacitors that have a 10-year service life after which they leak and damage the circuit board - unit is not repairable.
The 1992 units used better capacitors which won't leak. If you're interested in...
FINALLY, someone else who can confirm that there are TWO shorting plugs. Only one of them is actually called the SPOUT (SPark OUTput) though.
The "Ford 1991 Car Wiring Diagrams" shows TWO shorting plugs - one at D-26 and the other at D-70.
#1 @ D-26 has two yellow/green wires (#324 -...