I bought an aftermarket radio system from Autozone to replace the old one (Panasonic that didn't display anything), and couldn't get the wirings to power the interface, even with every wire color matching, they were twisted together and covered with electrical tape. I returned it and afterwards, the speedometer, odometer and map lights weren't working. The truck began to drive REALLY differently. The engine was overrevving, the transmission shifted SUPER rough and the power steering was weaker.
1993 Ford F150 XLT with 345,700 miles total, 145,700 on new engine and transmission.
unfortunately that's what happens when people start screwing around with wiring you really need a complete wiring diagram I personally use all data diy.com for Ford wiring harnesses but now that it's been messed up I'm assuming they've probably shorted out either wiring and or computer modules when they did that work.that's why it's best if people don't understand stereos to pay a stereo store to install it that's all those guys do
Thank you for your insight, Scotty, greatly appreciated.