I have a 1990 GMC Sierra 2500 that wont start. Nothing happens when I turn the key. A week ago I took it to get a tune up since it been shutting off on me and needed new wires. It has been working well for the past week and now it gave out on me. The battery has power since the lights go on and the starter was replaced last year. I am starting to get frustrated and just looking for any kind of help. If you had this problem or know what may be causing it please let me know. Just want to put my money in the right place since money is tight right now for me.
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1990 GMC wont go on
- Thread starter aivzdog
- Start date
I'd start with the basics. Charge the battery overnight, and then do a battery voltage under load test, using at least a 125 amp load. Most auto parts stores will do a free battery load test, after you charge the battery. Make sure your battery terminals and cables are making good contact . Double check those items. Measure the battery voltage with the key in the off position , to be sure the voltage reads at least 12 to 13 volts. Use an independent voltmeter or multimeter for these tests, and not the truck voltmeter. You can check the accuracy of your multimeter by checking the battery on another vehicle. A reading of 12.5 is normal if the vehicle has been sitting overnight. Turn on your headlights, and see if they pull the battery voltage down to less than 11 volts with the key in the off position. Anything lower might indicate a bad battery. Turn the key to start, and see what happens to the battery voltage. If there's no voltage difference between the key being in " on" position, and in " start" position, then no current is getting to the starter solenoid. That can be a bad ignition switch , or bad wiring circuit to the solenoid, or a bad solenoid. If turning the key to "start" does pull the battery voltage down to about 11.5 volts, then current is reaching the solenoid , but not the starter motor. If turning the key to start pulls the battery voltage down to 10.5 volts, then current is also reaching the starter motor. The starter motor may be jammed, due to loose starter to block bolts, improper shims, a bad starter pinion gear or bad flywheel teeth. If you suspect that no current is reaching the starter soleniod, you can try using a jumper wire from the positive battery terminal to the solenoid +12 volt connection, if you can identify that connection. Use a small gauge wire, and be careful not to short the wire to any place else on the truck. If you create a lot of sparks during this test, check your fuses before proceeding. If you have a stick shift, be careful that the vehicle will not move if you activate the starter motor.
Most starter solenoids make a clicking sound if power is reaching them when the key is turned to start.
The age of electronic control modules and the like have complicated matters. However, over the years, I've found that problems such as yours are caused by these issues, in most to least likely order; Bad battery terminals or cables; bad battery; bad ignition switch ;blown fuse ; bad solenoid; bad wiring to solenoid; bad or jammed starter motor. Occasionally, a "safety lock out" circuit , such as a switch connected to the shift lever or clutch pedal, is at fault. Turn the key to start while wiggling the appropriate lever may reveal the problem. Good luck !
Most starter solenoids make a clicking sound if power is reaching them when the key is turned to start.
The age of electronic control modules and the like have complicated matters. However, over the years, I've found that problems such as yours are caused by these issues, in most to least likely order; Bad battery terminals or cables; bad battery; bad ignition switch ;blown fuse ; bad solenoid; bad wiring to solenoid; bad or jammed starter motor. Occasionally, a "safety lock out" circuit , such as a switch connected to the shift lever or clutch pedal, is at fault. Turn the key to start while wiggling the appropriate lever may reveal the problem. Good luck !
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