1997 GMC Jimmy

I have a 1997 GMC J iimy and am having problems withit starting.I turn on the ignition switch and no lights on the dash,truck will turn over but not start.I can turn the key on and off repeatedly and the dash will light up and it will start. I tried putting in new relays in the glove box when it wouldn't start but nothimg happened.I took a test light to the fuse panel and the battery circuit for the ecm is dead but when the dash finally comes on so I not it will start the fuse for the ecm battery is energized. Is ther a relay I don't know about or what might be the cause of my problem.I can't smell any burned wires and this has just happened within the past week
Thanks Harley3717

Dude your Jimmy needs an ignition switch they are noted for complaints of this type! You can get transmission codes,weird problems caused by a loose connection internally of the ignition switch. I must of replaced at least a 100 of these in the past year!