Sounds like you've got a bad ground. Follow the wiring all the way to where the wires are attached to the body. If you do that, and find a loose nut/bolt, that is your problem (it would give you an intermittent short-to-ground when you hit a bump).

As for the check engine light, it's flashing because it's showing a trouble code. I'd recommend going to AutoZone or Advance and picking up a Haynes manual; the manual will have all the codes in it as well and what they mean.

As for the ABS light blinking, sounds like you have a problem with the ABS sensor that is mounted in the rear axle housing (it'll be next to the split box for your brake lines), in the modulator, or in the wiring shorting out to ground. Again, check the codes in the Haynes manual, and they should give you some idea on where to start. Also, if you have a Ranger that was built prior to 1996, you have the On-Board Diagnostic, Stage I (OBD I) computer and diagnostic system. After 1996, everything was Federally mandated to be mostly all the same. Therefore, AutoZone cannot simply plug in a code machine and tell you what's going on with your truck.

Also, for the guy who started this thread: One, clarify your sentences so everyone else can understand you (not trying to sound dickish, it just makes it hard to understand your problem). Two, unless you grounded the plug-and-play harness, it can cause problems--I've heard of people who have had electrical issues right where the trailer harness connects to the wiring harness for the brake lights/backup lights/turn signals. In other words: CHECK YOUR GROUNDS. You'll probably find the solution to your problem in that realm, electrically-speaking. To do so, a continuity tester light, or DVOM, would be a really helpful tool to have.

__________________
Billie, my "sparkly" blue 1992 Ranger
SPECS: 2.3 I4; Rebuilt motor at 194,263 miles; straightened driveshaft when engine was rebuilt

FIRST MODS: 2" suspension lift and rear disc brake conversion