See my post 92 ranger fault codes 18,19.
READ AND FOLLOW the repair manual. I short cutted some checks and it took
me till I redid the checks the RIGHT way to find and fix the problem. I
did find some other things that needed to be fixed, and came out ahead by
fixing it my self. and the knowlage I gained I cant put a price on. BUT
READ and follow the manuals. you'll fix it quicker and with less head