Quick answer. This 2010 Nissan Maxima got a new alternator that the customer bought and had ready. Our tech confirmed it was the right part, installed it, and a voltage test showed the battery was getting the correct voltage. But the wiring plug that connects to the alternator was melted. Our tech got the damaged wiring connected, and the car still needs a new pigtail harness. Labor on the record was 2 hours at $150, or $300.
Key Points
- The worst finding was not the alternator. It was the melted wiring plug that connects to it.
- The damaged wiring is connected, but it is not repaired. It still needs a new pigtail harness.
- The customer supplied the alternator. Our tech checked that it was the right part before installing it.
- After the install, a voltage test confirmed the battery was getting the correct voltage.
- A good voltage test today does not make a melted plug safe to forget about.
Read our guides a lot? Star Supercanic as a source in Google and our new posts show up more often in your Top Stories.
What Our Tech Found
Start with the part that is still open. The wiring plug that connects to the alternator is melted.
Our tech was able to connect the damaged wiring. That is not the final fix, and the record says so. It calls this a future issue that still needs repair.
The car needs a new pigtail harness. That is the short section of wiring and the plug that connects to the alternator. Our tech showed the damage to the people at the car and took photos.
The record does not say what melted it, so we will not guess here. It also does not show a harness repair on this job.
What Was Done
The customer bought the alternator and had it ready before we arrived. A part someone else bought still gets checked. Our tech confirmed it was the right one for this 2010 Maxima, then installed it.
After the install, our tech ran a voltage test. It confirmed the battery was getting the correct voltage. The record does not list the reading, so we will not print a number for this car.
2010 Nissan Maxima, November 6
Came in with: an alternator job, with the part already bought by the customer.
Our tech found: the wiring plug that connects to the alternator was melted.
What was done: confirmed the part, installed it, connected the damaged wiring and ran a voltage test.
Still needed: a new pigtail harness.
Labor: 2 hours at $150, or $300.
Why a Bad Connection Matters
This part is general background. It is not a report on this Maxima. AA1Car's charging system guide says a poor connection increases resistance and causes a voltage drop across that connection. That reduces the current moving through the charging circuit and can force the alternator to work harder than normal.
The same guide spells out the worst case. If there is no charging output at all, it says you may have 20 minutes to an hour of driving time before everything goes dead. The engine can stall, and the battery may not have enough reserve to restart it.
So a connection is not a small thing. It is part of the path the power takes.
What a Voltage Test Tells You
Part maker MSD Ignition says a common trouble sign is a meter reading 11.5 or 12 volts at idle, when it should read closer to 13.5 to 14.5 volts. MSD also says to check the circuit first, so you know the connection between the alternator and the battery is not adding resistance. The test for that is called a voltage drop test.
AA1Car gives one rule for it. With the engine idling, ideally the meter reads less than 0.2 volts between the battery positive post and the alternator's output terminal. A voltage drop test only finds a problem with current flowing and a charging load on the system.
This car has one more layer. The 2010 Maxima owner's manual says it has a variable voltage control system. That system measures how much electrical discharge is coming from the battery and controls the voltage the generator makes. Generator is the word Nissan's manual uses in its drive belt drawing, where you would expect to see alternator.
Before You Buy Your Own Alternator
Buying your own part can work. This job shows the check that should come with it. A part has to be the right part, and the wiring it plugs into has to be sound.
AA1Car makes both points. It says a replacement should have the same power rating as the original. It also says many alternators get returned because of faulty diagnosis or an overlooked problem that caused a repeat failure. Its advice is to check the wiring harness and terminals for voltage drops in the charging circuit connections.
That is general advice for any alternator job. On this one, the wiring is what our tech flagged, and the note and the photo are on the record in Shop Desk, the software our San Jacinto shop built.
A Recall Worth Checking
This one has nothing to do with the alternator. NHTSA recall 09V-358 covers certain 2009 and 2010 Altima and Maxima cars. It says the upper front strut insulators may crack. If one does, the strut rod could come out of its mounting position, which could affect stability and raise the risk of a crash.
The remedy was new left and right insulators from a dealer, free of charge. The recall applies to certain vehicles, and our record does not show if it was done on this car. You can check yours with your VIN on the NHTSA site.
Frequently Asked Questions
What is a pigtail harness?
It is the short section of wiring and the plug that connects to the alternator. On this Maxima, that plug was melted and the harness still needs to be replaced.
If the voltage test passed, why replace the harness?
Because the test and the plug answer two different questions. The test showed the battery was getting the correct voltage after the install. The plug was still melted, and our tech only connected the damaged wiring. The record calls it a future issue that still needs repair.
Can I buy the alternator myself?
On this job the customer did. Our tech confirmed it was the right part for the car before installing it, and the labor line was 2 hours at $150.
How much labor was on the record?
The record has one labor line, 2 hours at $150. That is the only time on the record for this 2010 Maxima, and it does not break the job into steps.
What did the melting?
The record does not say. It says the plug is melted and needs to be replaced. We will not name a cause our tech did not write down.
What We Read
- AA1Car, Alternator and Charging System Checks
- MSD Ignition, How to Test an Alternator and Wiring
- Nissan, 2010 Maxima Owner's Manual, Page 393
- NHTSA, Recall 09V-358
Supercanic tip: Replacing an alternator? Ask your mechanic to look at the plug too, not just the part. Call us at (951) 904-2477 and we will show you what we find.
Charging Trouble or a Bad Plug?
Bought the part already? Tell us when you call. We come to you and test it after the install.
