also check if the hazards are working. i had a problem with mine where the turn signals would not work on the left side, but changing the flashers for both turn and hazards fixed that. and of course check the bulbs to make sure they are indeed still operational
as for the wiper motor, check to see the switch is plugged in all the way into the plug and that you are getting power to it as well. also, check for power at the motor itself and if you are getting power, it could be that the motor is either seized or just plain burnt out. hope this helps!
And welcome!
oh, and as far as a check engine light is concerned, you should take a picture of that and post it here. ive never heard of a 79 with a check light for ANY vehicle prior to 1984. and then obd was only on some models....
_________________

To the Oquirr hills for awesome thrills! Go-go 4wd, Activate!