Hi folks, I have a 2006 Mazda5 with 477,000 km on it . At this point it is really just a backup car. After about a year of not driving it I have decided to bring it back to life as a fun project.
Previously it had stalled on me because the alternator was at the end of its life. The battery light went on at that time, i.e. about a year ago. I have just replaced the battery and the alternator but the battery light is still on. I have found this thread, just wondering if anyone has any additional ideas.
When I was removing the old alternator I wasn't very nice to the alternator harness as it was seized and pretty much welded in . After I replaced the alternator and the battery and noticed the battery light was still on I took some voltage measurements:
1) Engine off: battery: about 12.6 V
2) Engine on, voltage at the alternator terminal: 13.5 V
3) Engine on, voltage arriving at the battery terminals from the alternator: 13.2 V
4) Engine on, battery disconnected while engine running, voltage at the terminals: 13.2 V
5) Engine on, battery disconnected while engine running, all electric things turned on: 13.1 - 13.2 V
So, even without the battery the alternator was able to handle the workload just fine, the engine was still running.
Q1. Do these voltage readings look normal to you? Most websites mention the alternator should produce around 14.6 V, which, if true for Mazda5 as well, could imply the aftermarket alternator is not as good as the OEM one.
Q2. Since the alternator can run the car on its own and there's charging voltage at the battery terminals, it safe to drive the car? I have taken it for two drive tests already, about 1 hour each, the car was running fine.
Q3. Assuming the harness is all right (going to check it next), what else could possibly be wrong? Is there perhaps a single wire that I should check which is responsible for the battery light turning on/off?
Thanks for any ideas.
Previously it had stalled on me because the alternator was at the end of its life. The battery light went on at that time, i.e. about a year ago. I have just replaced the battery and the alternator but the battery light is still on. I have found this thread, just wondering if anyone has any additional ideas.
When I was removing the old alternator I wasn't very nice to the alternator harness as it was seized and pretty much welded in . After I replaced the alternator and the battery and noticed the battery light was still on I took some voltage measurements:
1) Engine off: battery: about 12.6 V
2) Engine on, voltage at the alternator terminal: 13.5 V
3) Engine on, voltage arriving at the battery terminals from the alternator: 13.2 V
4) Engine on, battery disconnected while engine running, voltage at the terminals: 13.2 V
5) Engine on, battery disconnected while engine running, all electric things turned on: 13.1 - 13.2 V
So, even without the battery the alternator was able to handle the workload just fine, the engine was still running.
Q1. Do these voltage readings look normal to you? Most websites mention the alternator should produce around 14.6 V, which, if true for Mazda5 as well, could imply the aftermarket alternator is not as good as the OEM one.
Q2. Since the alternator can run the car on its own and there's charging voltage at the battery terminals, it safe to drive the car? I have taken it for two drive tests already, about 1 hour each, the car was running fine.
Q3. Assuming the harness is all right (going to check it next), what else could possibly be wrong? Is there perhaps a single wire that I should check which is responsible for the battery light turning on/off?
Thanks for any ideas.