89 XJ - No Power At All

I've only had the truck for approx a week so looking for a direction to look in. Was driving the truck home and it started stalling and the radio cut out. I instinctively thought the battery leads may be loose and wiggled back and forth in the truck - things came back on and the truck started up fine. Kept driving home and the symptoms returned - radio cut out - engine stalling. I couldn't keep it alive by applying more throttle so I pulled over and had a look at the battery leads they're fine. Truck won't start when the key is turned at all. In ignition on the Radio won't work and neither will the blower. Checked the battery connections to relay and they are fine as well. Is there a main fuse for the truck somewhere? From inside it's like the battery isn't connected at all. I can turn the headlights on and that is the only electrical item that seems to work. Please give me a hint where to start!

Truck is a completely stock '89 Jeep Cherokee Sport 4.0L 5spd 4X4

Not sure what "looks fine" means.

Clean your cable ends, renew all grounds--passenger fender well for the starter relay, dipstick tube, where the main ground mounts to passenger side of the block, and don't forget that mean bastard that runs from the back side of the head to the firewall.

Remove the wires and clean the contact surfaces with sandpaper or a dremel tool, would be best to treat with corrosion inhibitor (at any hardware store).

Once that is done there are other things to check, but start with those.

I've checked the ground and all plugs/relays near the ignition coil. Cleaned and retightened the leads. I'm suspecting possibly the ignition switch may be bad - i'm going to see if I can check for power at it. Is it common on these trucks? I've only had the truck a week so i'm unfarmiliar with the "common stuff" on Jeeps but have worked on other cars quite a bit in the past. I also checked all fuses under the dashboard.

Joe_Peters thanks for your reply.

Search... Grounds are the big thing with these renix years..Like he said, CLEAN and or replace grounds..I did mine and it up with alot of stuff..Do some reading you will learn alot from these guys on your jeep

Ignition Switch was the culprit - Black 4 pin offset connector seems really loose in the joint. Thanks for all the help guys, i'm back on the road!