GMC 97 Safari Electrical Short

[xlPhobialx]

The other day I was driving and all power to the vehicle suddenly went out. I had to cruise into a parking lot. I have had the alternator tested to be good at Auto Zone and the battery tests just fine with the multimeter. When I checked the fuses under the hood I saw that the 40A Ign A fuse blew. I replaced it with another 40 and tried starting the vehicle and it blew again. I did some testing with a test light by placing the metal clamp of the tester light on the negative connector and than poking the negative terminal with the needle of the tester light, the bulb would light up even though the car was off meaning there is a short somewhere. http://www.youtube.com/watch?v=pjXt7_gusgM

So I kept that in place and took out fuses until the light went off to find out what circuit the short would be on. It ended up being the 50A Batt fuse. This is when I went up to Auto Zone to have the alternator tested as some guy had a similar problem and it ended up being a bad alternator. The techs there said maybe it is a short in the ignition switch or something. I have no idea how the 40A Ign A fuse could blow but yet the short is in the 50A Batt fuse. Any ideas and help would be appreciated in getting this fixed. Thank you.

[Blue Bowtie]

If you are still chasing this down, you will need schematics for the power distribution system. You will use those to determine how to isolate any apparent grounds. You will also need an ohmmeter for testing since he test lamp will not provide any clue as to the amount of resistance to ground. A voltmeter will also be useful to verify circuit voltages from devices, such as the ignition switch or regulator.

[vettepin]

check your starter wires for a short to the frame. when you find the fix please post how and what it was for future victims.....