Google clicky starter.

The best way to fix it is to put a relay in the starter circuit. That way your starter solenoid gets plenty of juice. This is pretty common on Sierras that are getting on a bit.

That's the one!!!!!

Steknig can appreciate the situation, as he is also getting on a bit

My knee go's CRACK, not click.

How old are you ya prick?!?!?!?!?!?

Old enough to know better!

I did the relay thing to a car once and yes it worked but honestly its just a band-aid for a number of different problem.
If you check you battery and it is in good working order (be sure to load test it). Check your charging system. Then look at your wires at the starter, Altinator and at the battery.
Check to see if there is any disscoloration of the wire sheathing. If there is your starter or wiring is pulling to many amps and burning your wiring causing your starting problem, If that is all ok then slice the sheathing back a little take a good look at the wiring under it, is it full of white powdery stuff or discolored? This is caused by a few different things but it too causes a big amp draw causing your car not to want to start.
If all that is ok you need to take a look at all your connections, have a look at the signal wireclean up the wire end and where it plugs onto the starter. Check your ground connection. Take it off clean it up with a wire brush clean up the connecting area and the nut that holds it down.

You do have a point. But if I was going to the trouble of replacing wiring I would put a relay in there anyway.

Oh shit i'm starting to sound like Nissvit

Google clicky starter.

The best way to fix it is to put a relay in the starter circuit. That way your starter solenoid gets plenty of juice. This is pretty common on Sierras that are getting on a bit.