hi, i have a 90 k1500 yesterday i used my headlights around about 7 turned my truck off and came back to go to work around 8 and both high and low beams just stopped working. i checked the fuses and the ground wire and its not that. any suggestions

So you mean that you have no headlights at all ?
I have seen one instance where the tan wire had shorted to ground inside the steering column.
Or, could be the dimmer switch, light switch, hard to tell without using diagnostic equipment and having the vehicle.
Could be loss of the ground for the headlight circuit. Sorry my wiring diagrahm does not tell me the location of said ground.
This is'nt much but I hope it might help.

I've found corrision in the connections to the lights. Use a 12 volt test light and check for power to the connection. Follow it to the fire wall plug and check this.
http://www.alldata.com/ They have good wiring diagrams. Cost appx. $25.00 for a years subcription. Really this is cheaper than throwing parts at the problem.

hi, i have a 90 k1500 yesterday i used my headlights around about 7 turned my truck off and came back to go to work around 8 and both high and low beams just stopped working. i checked the fuses and the ground wire and its not that. any suggestions

If the fuses are good the problem on a vehicle this old is the fuseable link....you will need a meter to find this problem...I would start at the starter after conferming that there is no 12volts at the lamps and the ground is good..