92' runner randomly won't turn over. Doesn't seem to matter if it's hot, cold, etc. You turn the key, fan comes on, but no click, and starter doesn't do anything. You can wait 10 minutes and come back and it fires right up. Last time we ended up bump starting it and none of the guages or the radio worked. Tested the solenoid and it seems to be fine. Came out next morning and it fired right up. Got any suggestions?

Mods related to problem (electrical or location) are headers, arb onboard air/lockers, clifford alarm, recently did a full tune up and oil change.

Thanks for any help!