What else is there to look at?
Battery Replaced. Alternator Replaced. Car Still Dies.
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Follow the electrical trail. There is a fusable link that runs from the alternator to the starter and from the battery to the starter. There are instances of the starter becoming highly corroded and causing electrical issues. Check the continuity from the alternator to the battery. Chack the ground to the engine. It is on top of the head near the front under the cover.
We had a recent instance of a car with a new battery and a known good starter not starting. He checked all the fuses and they looked good. He removed and reinserted the BCM fuse near the foot well and the car started right up. Fuses can look fine but still not passing current. My 30 tech repair friend told me to always put an ohm meter across a fuse to verify it is still working.
If it starts and then dies, its possible that the BCM has forgotten the key chip and the security system is shutting it off. If the green key shows up in the idiot lights and stays on, the car will start and run for about a second then shut off. The relearn process is in the owners manual. its also on this forum in several places. It is something like turn the key to run without starting, wait till the green key goes off then wait for 10 minutes. Repeat a total of three times and the BCM will relearn the key and it should run if this is your issue.
Good luck
We had a recent instance of a car with a new battery and a known good starter not starting. He checked all the fuses and they looked good. He removed and reinserted the BCM fuse near the foot well and the car started right up. Fuses can look fine but still not passing current. My 30 tech repair friend told me to always put an ohm meter across a fuse to verify it is still working.
If it starts and then dies, its possible that the BCM has forgotten the key chip and the security system is shutting it off. If the green key shows up in the idiot lights and stays on, the car will start and run for about a second then shut off. The relearn process is in the owners manual. its also on this forum in several places. It is something like turn the key to run without starting, wait till the green key goes off then wait for 10 minutes. Repeat a total of three times and the BCM will relearn the key and it should run if this is your issue.
Good luck
Fusable link!!
It's kind of a pain to check. It is easier done with 2 people. You need to do a resistance test between the starter and the post on the alternator. If the resistance is > 20 ohms or it's an open circuit then the fusable link is no good. In order to replace the link you will have to take the intake manifold off and open up the wiring harness that runs between the starter and the alternator to remove the wire. Then you can replace the fusable link section of the wire.
I helped another user out with diagnosing and repairing. If you do an advanced forum search putting in my username and "fusable link" you should be able to locate it pretty easily.
It's kind of a pain to check. It is easier done with 2 people. You need to do a resistance test between the starter and the post on the alternator. If the resistance is > 20 ohms or it's an open circuit then the fusable link is no good. In order to replace the link you will have to take the intake manifold off and open up the wiring harness that runs between the starter and the alternator to remove the wire. Then you can replace the fusable link section of the wire.
I helped another user out with diagnosing and repairing. If you do an advanced forum search putting in my username and "fusable link" you should be able to locate it pretty easily.
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First thing I check is to see if the security system is shutting it down. Look for the green lock in the dash display
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If it will start and run, look for the battery icon on the IPC. If the generator or the fusible link is bad that should be on.
Not necessarily.... The alternator is producing power as it should be and the problem exists in a connection between the alternator and the rest of the vehicle.
Common alternator dummy light wiring.
battery + ======= LAMP ======= alternator output +
This done using a wire that is not attached to the rest of the cars electrical system. It is a direct attachment to the alternator. If the output from the alternator fails that "+" in the above diagram turns to a "-" and the light will come on. Because there is no issue with the alternator it is outputting the + as it should be no light will come on.
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If the car is having problems that are electrically induced, then power from the generator is not getting to where it is needed, and the system should detect that.
The battery warning is lit by the ECM or BCM, so it probably isn't just a wire between the generator and the battery.
Nope it will not detect that. all will seem fine and out of no where the car will die. no warning no light. It is only designed to check to make sure the alternator is outputting voltage not if that voltage is actually making it to the rest of the vehicle. The reason why "voltage" as a measurement is not used is because of load. Load on the charging system can and will cause the voltage to drop really low. This is a normal way the system works so if you have a 300 amp draw from say a car audio system if voltage is what was looked at the alternator light would be blinking every time a song hit a deep bass note. That doesn't happen. The ECM just checks to make sure the alternator is outputting and that is done in a manner that isolates it from the rest of the electrical in the vehicle. Kind of like what I showed in the diagram in my previous previous post.
Look at the wiring diagram below There are 2 wires that come off of the alternator that are connected to the ECM. One of the wires is for the field and gets sentfrom the ECM to the alternator to energize the field so the alternator creates electric. The other wire sends voltage from the alternator to the ECM this is how the ECM knows the alternator is working or not This is a completely different circuit then where the fusible link is.
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an alternator only needs a single wire connected to it for it to generate power. That is the field signal wire. The housing of the alternator must also be grounded to the same ground as whatever is sending the field signal. They are not like the old school alternators that had external voltage regulators and has diodes and a grip of wires attached to it. everything is internal now. But in order to make sure the alternator is outputting and the low voltage on the power system in the vehicle is not load induced an isolated circuit is used.
an alternator only needs a single wire connected to it for it to generate power. That is the field signal wire. The housing of the alternator must also be grounded to the same ground as whatever is sending the field signal. They are not like the old school alternators that had external voltage regulators and has diodes and a grip of wires attached to it. everything is internal now. But in order to make sure the alternator is outputting and the low voltage on the power system in the vehicle is not load induced an isolated circuit is used.
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Hi KG,
I have the full manual set. Is this from the manuals or a different source?
It is from the shop manuals but has been made to be interactive so a person is able to click on a wire and it will highlight that wire even across several pages.
This is what it looks like right out of the shop manual.
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Where or how can one get access to this version?
Thanks, I have a digital version which seems to be PDFs pulled from a GM service website. They are extremely helpful but KG' interactive version picked my interest.
It costs about 250.00 USD a month to access what I have access to. It gives you the repair manuals made for most vehicles made. It also does pricing of parts and labor as well.
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I would try something simple first. Dirty throttle body can do this. Has to be spotless clean inside and both sides of the throttle plate.
How does a dirty throttle body end all electricity in the car?
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"car still dies" This means stalls out after it starts?
If you are sure its electrical start with the connections on the junction box above the battery.
Good luck..
If you are sure its electrical start with the connections on the junction box above the battery.
Good luck..
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It doesn't.
There is, or can be, a difference between "Car still dies" and "ends all electricity in the car". You need to either fully describe the symptoms you are having, or link to the thread in which you do so that I can merge the threads.
Also, finding electrical problems pretty much requires the use of a volt meter, Do you have one, and can you use it?
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