1990 S10 Blazer electric problem??

we have had this blazer engine rebuilt after sitting for 2 years and gotten a new alternator. Here are the problems i would appreciate any advice:
1) about a month ago the wipers were being used then we went to turn them off and they wouldnt turn off.
2)Then the brake light on the dash likes to come on occasionally for no reason at all (i have noticed it when pressing the brakes)
3)when driving early morning we have the headlights on and radio and the headlights will get real bright and the dash indicator lights ( check engine and all the other ones ) will go crazy. this happened again this morning but it shut the whole blazer off. took a couple tries to get it started but it did start finished drivin the hour took work and made it home.

we checked all the ground wire all were tight. The 3rd one is the one that concerns us the most.

Thanks for any help!!!

when it shut it off we had no interior lights at all and no headlights the only lights that worked were the hazrds and brake lights

sounds like something to do with the ignition switch or key tumbler in the steering column.