Electrical issues after alternator replacement.

Nix

New Member
#1
Hello, forum -- new member here with a question for those of you who may have dealt with this issue (or for anyone who might have it in the future, perhaps it will be of help).

I'm working on a 2009 Corolla XLE with the 1.8L four cylinder clocking a little over 170k. Wife was driving it home last night, electrical system dims/sets about failing, car stalls and dies. Immediately I'm thinking alternator.

Have her towed home, get her started and running again, multimeter shows less than 12V on the battery at idle under load. Okay, good enough for me -- alternator.

I get a replacement, get it home the next morning, perform the change and change the serpentine belt while I've got it off.

Upon firing her back up after the replacement, she stumbled as she started, came up to idle and levelled out -- but ...

  • ABS fault indicator on
  • TPMS indicator on
  • Airbag indicator on
  • Electric power steering system indicator on (power steering not functioning)
  • The odometer LCD does not display the transmission's gear (in park) and it will not shift out of park
  • No electric system (battery) indicator

It finally dies after running for a minute or two. I charge the battery for some time to be able to get her running again, and upon testing the battery at idle and directly testing the alternator output, I'm still getting less than 12V with the replacement alternator. The alternator is a Carquest reman from Advance Auto. I'll be bringing it back up there tomorrow for them to bench test it along with my battery. I'm assuming it's a combination of a fried battery and a bad re-manufactured alternator, but I'm not positive.

All fuses and relays check fine. I even tested my multimeter on another car's charging system to be sure I wasn't a) out of my mind and b) that the meter wasn't faulty. Second vehicle checked fine, normal charge output under idle/load.

Anyone have any insight as to what might be going on? I'd appreciate any advice someone has to give, especially if you've dealt with the same issue after an alternator replacement.
 
#2
Based on your description, I tend to agree with your assessment that is probably a problem of the battery and the alternator.
One quick suggestion - you may have already done this in your troubleshooting - totally disconnect the battery from the car for a minute and then reconnect it. This resets the CPU which controls the ABS/TPMS/Airbag indicators, etc. This solved a similar problem I had with my 1991 Camry' dash indicator lights when I changed the alternator.

If your battery is older than 4 years (or maybe it is the original), you should replace it anyway.
On these remanufactured alternators (even those from the dealer), I was surprised to learn that the internal voltage regulators are not replaced unless they test bad...so a reman alternator might test good on the factory bench but fail under real load conditions. Perhaps you should return the CARQUEST alternator for another and see if there is a difference. I had to return a rebuilt alternator for my Camry to Auto Zone because it was dead on arrival.

Please let us know how this turned out.
 

Nix

New Member
#3
Based on your description, I tend to agree with your assessment that is probably a problem of the battery and the alternator.
One quick suggestion - you may have already done this in your troubleshooting - totally disconnect the battery from the car for a minute and then reconnect it. This resets the CPU which controls the ABS/TPMS/Airbag indicators, etc. This solved a similar problem I had with my 1991 Camry' dash indicator lights when I changed the alternator.

If your battery is older than 4 years (or maybe it is the original), you should replace it anyway.
On these remanufactured alternators (even those from the dealer), I was surprised to learn that the internal voltage regulators are not replaced unless they test bad...so a reman alternator might test good on the factory bench but fail under real load conditions. Perhaps you should return the CARQUEST alternator for another and see if there is a difference. I had to return a rebuilt alternator for my Camry to Auto Zone because it was dead on arrival.

Please let us know how this turned out.
Good morning, Tom --

I chatted with a friend of a friend who is a master Toyota tech and he gave me the insight to check the fusible link in the under-hood box. I had begun to have a suspicion through research that I might have fried it when I reconnected the battery and alternator Saturday.

Sure enough, I brought both the battery and alternator to test at the parts' shop and they tested fine. I got a multimeter on the stud for the fusible link and it read no voltage. After the massive job of getting that fuse box assembly apart and the fusible link separated from it (harder than one would think) it was, in fact blown.

I've ordered the link and I expect it via FedEx either Tuesday or Wednesday, at which point I'll replace it and hem everything back up and see what she does.

That fusible link controls a lot of the electronics -- to include almost everything I'm having an issue with now, minus the transmission indicator and my lack of ability to shift out of park.

I didn't reverse the polarity on the battery when I reinstalled it, so it blowing the fusible link might have just been a freak thing. We'll find out when I get it replaced.

I do intend to keep everyone posted on this, and in the other forum I sought advice from; maybe it'll help someone in the future. I wish I had thought to take photos of the entire process -- that under-hood fuse box is a real beast to get apart, and disassembling it is nowhere near obvious.
 

Nix

New Member
#4
PROBLEM SOLVED:

For those of you that experience the same problem and symptoms as I did, here's a way to figure out what happened:

Cause of Issue

Upon reconnecting the battery after replacing the alternator, the under hood fuse box's main fusible link blew. I did not reverse polarity on the battery, which is a typical cause for the link to blow. It was honestly just poor luck.

If you experience these sudden systems after connecting/disconnecting your battery:
  • Loss of Electric Power Steering
  • Air Bag Indicator
  • Loss of Transmission Shift / No Gear Display on Odometer
  • Brake Fault Indicator
  • TPMS Fault Indicator
  • Alternator Has No Output
  • Remote Power Locks Not Functioning

AND/OR --

Your alternator tests good along with the battery, but the alternator tests no output (voltage tests the same as battery, even off of the output stud of the alternator)...

Check the fusible link!

To test it for voltage, remove the cover of the under hood fuse box. The large, clear-topped block on the left side of the box is the fusible link. In line with the fusible link closer to the battery is a stud that has no wiring connected to it - this stud can be tested. It should display the same voltage as your battery (approximately 12v, depending on your battery's charge/condition). If it displays no voltage, there is a blown component inside of the fusible link.

When the fusible link does blow, it evidently takes out every system associated with it. In this case, the transmission would not shift out of park, the cluster displayed no gear indicator, and all the other associated problems in the list above also appeared.

Removing the Fusible Link

In order to actually remove the fusible link, you have a JOB in getting the fuse box disassembled.

Before attempting to disassemble the fuse box, I recommend taking these steps:

  1. Disconnect the battery! Remove it from the vehicle to give yourself more room.
  2. Remove the air intake assembly.
  3. Remove the ECU. Disconnect the main connectors, but be careful - the plastic hinges that secure it in place are very fragile. Ask me how I know.
  4. Remove the fuse box cover.
  5. Disconnect the main hot wire from the front of the fuse box. The two studs underneath are main inline voltage and what ties the fusible link into the rest of the box. Unplug all the connectors in the center of the panel.

When disassembling the fuse box, BE PATIENT. It took me most of a Sunday to get it apart, because it is honestly that difficult. You do NOT have to cut or break anything in order to remove this link like videos on YouTube illustrate.

There are snaps around the entire outside of the box that hold the upper and lower parts of the box assembly together. Patiently work them apart. I found it easiest to start in the upper, right corner nearest the driver's strut tower.

Once you get the box disassembled, disconnect the main connectors from the bottom of the fusible link. You may find it difficult to turn the top of the box over with all the wiring - be gentle and patient.

After disconnecting the slotted connectors, reapproach the link from the top of the box. Around the outside edges of the box and the large mini-fuse panel at the top end of it are snaps that you cannot see. Work a screwdriver into the areas (they become obvious once you know they're there) and gently pry until you hear them pop free. Once you've "popped" them lose, the fusible link and the mini-fuse panel assembly will slide free from the top of the box. You shove it out through what would be the box's interior, because it is bracketed in place over the top. Those do NOT come off. Do NOT cut them out to get the link free, it won't help you. It HAS to come out from the bottom.

Several wires bolted to the fusible link with 10mm and 8mm screws need to be removed. From there, a single 10mm screw holds the mini-fuse panel to the fusible link.

I recommend taking pictures of the wiring and connectors in order to place them back in the correct order. The wiring length is appropriate ONLY to where they will reach where they are supposed to go, and the sizes of the eyelets match to their associated threaded holes -- but better safe than sorry.

Reassemble everything in reverse order. Utilize caution when handling the fuse box - the wiring and components aren't exactly fragile, but no sense breaking something in frustration or because of lack of patience.

It is a pain in the neck to get this thing apart. I cannot stress it enough: be patient; you DO NOT have to damage any part of that assembly to replace the link.

I wish I had taken pictures of the whole process, but it didn't dawn on me until after the work was complete.

I hope this helps someone in the future who was stuck in the same situation I was. Thanks to everyone who put in their words of wisdom; it helped me to rule things out!
 
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