Cannot find starter/solinoid on 95GMC Sonoma 2.2L 2wd

Why did it overheat, did you fix the overheating? Are you saying it cranks good but won't start? If it cranks good but won't start, check fuel--spark--compression. Make sure battery has a full charge and battery connections all good. If the battery is down, we can't do any testing. At the starter motor motor, two voltage circuits, one comes from the battery, hot all the time. The other voltage circuit goes hot with key in the crank position is wired through clutch switch. The starter motor grounds through engine block. Any testing at starter make sure tranny is in park or neutral and parking brake is set. You can have the starter motor tested.

have your fuses checked, or have your started checked, it might have burned out.

The problem is in the start circuit if the starter won't engage from the key. From battery to ignition switch to neutral park safety switch to starter relay to starter solenoid to starter to ground and back to battery-lights come on so switch is good, next check the neutral safety switch for power in and power out.
Once you get the start circuit working so starter engages from the key, then you can address the ignition circuit for possible no spark.

Do you have 12 volts at the large post and at the small wire coming from the key switch when the starter will not turn ?
There is a neutral safety switch in the circuit that could have failed.

If the security system was the problem the light would be flashing in the dash indicating activation and lock out.

COULD IT BE NUETRAL SAFETY SWITCH AND HOW DO i TEST IT . Try moving the gear selector to neutral an see if then it starts . If it does ,you need a transmission range switch ,for a automatic transmission . If it does the same in park an neutral , voltage drop test the main battery cablb an ground . How old are the battery cables ?
Starter Voltage Drop

Looking at a wiring diagram i see testing can be done at the starter relay ,or where in plugs into the fuse/relay box . Free wiring diagrams here http://www.bbbind.com/free-tsb Enter vehicle info. year , make , model an engine size. Under system click on engine ,then under subsystem click on charging system (has starting & charging under this subsystem ). Click the search button then the blue link.

If you're SURE the battery is good, it's either a loose wire, bad starter solinoid, or bad ignition switch. Check the wires on the starter, with the batter disconected of course. Make sure they are thight on the starter studs. If they are, you'll see two small prongs/studs, and one large one. THIS IS DANGEROUS ESPICALLY IF YOU HAVE A MANUAL TRANNI!!! An automatic wouldn't be a prob, but if it's a manual, make sure it's in netural and to be safe, a guy in the truck with foot on the brake. Take a small wire, and use it to jump current from the large stud to the small one with a wire hooked up to it. If it turns over, it's your ignition switch. If not, it's your starter solinoid. Solinoids can be replaced but most people just replace the whole starter. Hope this helps.

If you have a Volt Meter check the voltage at the large cable hooked to your battery. If it is at 10V + when you try to start it, check your spade connection wire on your starter for voltage when trying to crank. If battery volts, the starter is bad. If not, put your truck in neutral and try to start it. If it starts, your neutral safety switch is bad, if not it may be a fuse, or even your key switch. If under 10V+ at the cable on the starter, you have a bad connection at the battery or a bad cable. Clean both positive and negative cables with a wire brush and make sure connections are good and tight.

test starter solinoid wire from harness, with a helper put test light on wire get friend to turn key to start, light should light up, wires at the bottom of engine may (look) fine