Electrical nightmare
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8th Gear
Joined: Mar 2009
Posts: 8
Likes: 0
Electrical nightmare
First alternator went out, drained battery. Second (used)alternator with new battery, output 13.5 for 120 miles then erratically spikes to 17.5 down to 10.8. Installed voltage regulator. Second alternator runs thirty minutes around 13.5.
Cranked car two hours later runs down to zero. Third alternator (new).
Cranked car, not charging, battery runs down to 8 v within minutes.
Jumper cables hooked up let car run for approx. twenty minutes, still at 12 v. Shut car down go inside and pull remaining hair out for ten minutes.
Crank car again, remove jumper cables, reading 13.5v. Drive car for one hour using lights AC, radio,etc. 13.4-13.7.
Any suggestions to try?
Automotive electrical shop no help, GM dealer shop no help.
Cranked car two hours later runs down to zero. Third alternator (new).
Cranked car, not charging, battery runs down to 8 v within minutes.
Jumper cables hooked up let car run for approx. twenty minutes, still at 12 v. Shut car down go inside and pull remaining hair out for ten minutes.
Crank car again, remove jumper cables, reading 13.5v. Drive car for one hour using lights AC, radio,etc. 13.4-13.7.
Any suggestions to try?
Automotive electrical shop no help, GM dealer shop no help.
Drifting
Joined: May 2005
Posts: 1,590
Likes: 1
From: Littleton Colorado
How are the cables? At the starter, at the battery? Loose or corroded will not help you out. Also, there is a fusible link in the wire from the alternator to the starter. I'd test that wire to make sure its ok.
What battery? Red tops have a huge issue with being run down, most don't recover from it.
I'd also think about getting a trickle charger until you get it sorted out. I’d be concerned for the PCM when jumping it.
If all that checks out then Bill Curlee is the man to talk to, he can sort it out.
What battery? Red tops have a huge issue with being run down, most don't recover from it.
I'd also think about getting a trickle charger until you get it sorted out. I’d be concerned for the PCM when jumping it.
If all that checks out then Bill Curlee is the man to talk to, he can sort it out.
Tech Contributor
Joined: Jan 2007
Posts: 19,353
Likes: 1,125
From: Dyer, IN
First alternator went out, drained battery. Second (used)alternator with new battery, output 13.5 for 120 miles then erratically spikes to 17.5 down to 10.8. Installed voltage regulator. Second alternator runs thirty minutes around 13.5.
Cranked car two hours later runs down to zero. Third alternator (new).
Cranked car, not charging, battery runs down to 8 v within minutes.
Jumper cables hooked up let car run for approx. twenty minutes, still at 12 v. Shut car down go inside and pull remaining hair out for ten minutes.
Crank car again, remove jumper cables, reading 13.5v. Drive car for one hour using lights AC, radio,etc. 13.4-13.7.
Any suggestions to try?
Automotive electrical shop no help, GM dealer shop no help.
Cranked car two hours later runs down to zero. Third alternator (new).
Cranked car, not charging, battery runs down to 8 v within minutes.
Jumper cables hooked up let car run for approx. twenty minutes, still at 12 v. Shut car down go inside and pull remaining hair out for ten minutes.
Crank car again, remove jumper cables, reading 13.5v. Drive car for one hour using lights AC, radio,etc. 13.4-13.7.
Any suggestions to try?
Automotive electrical shop no help, GM dealer shop no help.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
The alternator charges the battery THRU the starter solenoid connections. VERY VERY common issue. The fuseable links, eyelet connections, and wires commonly have issues. CHECK THOSE wires!!!!
A easy way to see if thats the issue is to connect the POS battery terminal to the LARGE terminal on the back of the alternator and see if that fixes the issues. The other issue is the plug on the alternator. Make sure that the wires have the the correct voltages and they are making the proper connections to the alternator. BIG RED wire is the charging wire The small reds wires are 12 VDC battery voltage and Gen turn on signal , the others are 12 VDC a sense wire and alternator duty cycle wire.
Heres a schematic for you.
UNLESS,,,,,,you check the voltages and do some basic troubleshooting, you better have a BIG bank account. OH,,,,by the way,,,,,can I have all of your OLD parts????
CHECK THOSE WIRES AND VOLTAGES!!!!!!
BC
A easy way to see if thats the issue is to connect the POS battery terminal to the LARGE terminal on the back of the alternator and see if that fixes the issues. The other issue is the plug on the alternator. Make sure that the wires have the the correct voltages and they are making the proper connections to the alternator. BIG RED wire is the charging wire The small reds wires are 12 VDC battery voltage and Gen turn on signal , the others are 12 VDC a sense wire and alternator duty cycle wire.
Heres a schematic for you.
UNLESS,,,,,,you check the voltages and do some basic troubleshooting, you better have a BIG bank account. OH,,,,by the way,,,,,can I have all of your OLD parts????
CHECK THOSE WIRES AND VOLTAGES!!!!!!
BC
Last edited by Bill Curlee; Apr 29, 2009 at 01:48 PM.
Tech Contributor
Joined: Jan 2007
Posts: 19,353
Likes: 1,125
From: Dyer, IN
The alternator charges the battery THRU the starter solenoid connections. VERY VERY common issue. The fuseable links, eyelet connections, and wires commonly have issues. CHECK THOSE wires!!!!
A easy way to see if thats the issue is to connect the POS battery terminal to the LARGE terminal on the back of the alternator and see if that fixes the issues. The other issue is the plug on the alternator. Make sure that the wires have the the correct voltages and they are making the proper connections to the alternator. The reds wires are 12 VDC battery voltage, the others are 12 VDC a sense wire and alternator duty cycle wire.
Heres a schematic for you.
UNLESS,,,,,,you check the voltages and do some basic troubleshooting, you better have a BIG bank account. OH,,,,by the way,,,,,can I have all of your OLD parts????
BC
A easy way to see if thats the issue is to connect the POS battery terminal to the LARGE terminal on the back of the alternator and see if that fixes the issues. The other issue is the plug on the alternator. Make sure that the wires have the the correct voltages and they are making the proper connections to the alternator. The reds wires are 12 VDC battery voltage, the others are 12 VDC a sense wire and alternator duty cycle wire.
Heres a schematic for you.
UNLESS,,,,,,you check the voltages and do some basic troubleshooting, you better have a BIG bank account. OH,,,,by the way,,,,,can I have all of your OLD parts????
BC
