Car: 2003 Toyota Corolla Le Automatic Transmission 4 door Recent Repairs: New battery & Alternator
My 2003 Toyota Corolla LE Automatic Transmission has lost all power and the gears lock up(Can’t shift out of park) My battery light turns on and off but when I popped the hood and opened the fuse box and pressed down on a electrical connector that I believe leads to the battery/alternator, my hazard lights start blinking and I have to press the unlock button on my key to turn them off. I then am able to shift gears and all power returns. I had my alternator checked at a Auto parts store and they said there was a shortage with the alternator and so I replaced it and it fixed the issue for a day and then the same problem came back. I had my battery checked and was told that there’s nothing wrong with it. Any help will be very much appreciated! If I can provide anymore info, please let me know and I will do my best. Thank you so much for your time I appreciate any help I can get.
You have probably found the problem: a loose or corroded connection at the spot where you pressed down. Disconnect the negative battery cable and isolate it so it can’t make contact with the negative battery terminal. Then undo that flaky connection and clean it all shiny clean with a wire brush. Then reconnect it snugly.
Okay but what do I clean the connector with? I don’t know and I don’t want to ruin anything. It’s a alternator harness I think I am not sure if I should add liquid to something like that? I tried to do with a dry wire brush but it didn’t fix it.
Edit: It did look dirty, it had some brownish color to it.
First off, to minimize the chance of inadvertently making a minor problem into a big problem, before disturbing any electrical connectors, remove the negative connector from its battery post. If you don’t know how to do this, or don’t have the required tools, best to let a shop handle this problem.
Beyond that, here’s some ideas at least
Ask the parts store if they have an alternator test fixture. If so, take your alternator there to make sure it is working. New or rebuilt alternators can fail right out of the box.
If you know how to use a volt meter, you can do a couple of experiments. With the engine off, the voltage between the two battery posts should measure 12.5-12.7 volts. With the engine running, 13.5 - 15.5 volts. What does yours measure? With the engine running, measure the voltage between the alternator output post (on the alternator) and the battery positive. It should be between 0 and 0.3 volts. What does yours measure?
Yes before I tried cleaning it I removed the negative terminal and I will check the voltage on my rebuilt alternator and battery tomorrow. Do you think it’s possible that it’s the alternator harness(Not sure of name) the connector that’s located in the fuse box that leads to the alternator/battery that needs to be replaced or cleaned because when I press down on it my car will regain power and I am able to shift gears again until I turn my car off.
I should probably also mention that I have a aftermarket alarm in my car and it goes off for no reason and it may be draining battery or causing other issues.
Alarm System – Well THERE is the likely cause of much of your problems. I can’t count how many posts just like yours that have been made here with electrical “weirdness” on a car that has an aftermarket alarm. These alarms are often installed in a shoddy manner (shoddy by automotive standards) and over time they start causing battery drains, no-start conditions, random alarms and vehicle immobilization.
You might want to have the system completely removed and tossed in the recycle bin. And then start diagnosing your any problem that is left, if any.
Anything’s possible I guess. My Corolla’s alternator stopped charging the battery one time, and after a lot of diagnostic work I discovered battery acid had worked its way down the inside of the wiring harness to a wire splice, promptly ate it, and disconnected the alternator charging wire from the battery. If you think there’s a high resistance problem between the alternator charge output and the battery, measuring the voltage drop along that path with the engine running as described above is the way to confirm it. There are other connections for the voltage regular function which are less easy to debug. But problems with the voltage regular usually show up in the other voltage measurements I mentioned above.
And yes it is possible to have a 100% working battery and alternator and some circuit in the car drains the battery overnight. This is diagnosed using a phantom-current-drain test. Just a measure of how much current remains flowing out of the battery with the engine off. Should be less than 50 mA. On my Corolla it measures 7 mA.
PLEASE somebody help me. I have one quick question. This youtube video shows my exact fuse box (Skip to 2:00) What is the white connection called? It’s on the bottom left, It has a wire connected to it. This is causing me problems and I have to press it down to regain power everytime I restart my car… I want to replace it but can’t figure out what it is.
The wire is part of the engine wiring harness. This is connected to the engine room junction block. To buy new replacement parts would be very expensive. Ideally a technician would repair this connection if possible.
This is the power wire from the battery to the junction block. Unplug and examine it and see if you can replace the terminal on the wire and clean the junction block terminal.
Thank you for quick reply! I don’t think it’s broken but has a bad connection. How would I go about cleaning this connector? Do I need to take it off to clean or can I just unplug and clean with a contact cleaner with battery disconnected.
Disconnecting the battery may not be necessary, but a wise precaution if you are not sure. On many cars you’ll lose radio presets: do you have the code to re-enter and get the radio working again?
I’d start by unplugging the connector and taking a close look for corrosion or anything unusual in the wires and individual connections on both sides of the connector.
I have lost radio presets but I can just reset them again later. I noticed a brownish color on the connectors near the fuse box and I am not really sure how to go about cleaning them. What would I use to clean them with? do I just unplug then connector and battery then clean it or would I have to completely remove the connector somehow to clean. I am pretty lost when it comes to anything electrical. My car has power right now but the battery light is flickering probably because of the bad connection. Does this sound like something serious or something cheap & easy to fix?
It doesn’t sound expensive if I am hearing you right. So when you press on some part of that fuse box in the video - one of the white relays that are plugged into the fuse box? - the circuit works again? That localizes the issue.
Like others here, I think the installation of the aftermarket alarm system is suspect. It can take some time to find out where its connections were made and repair them, or undo and repair them.
I am planning on having the alarm removed by a specialist tomorrow. Do you think if the alarm is the issue and I remove it, the problem will go away? Do I need to fix the issue while the alarm is still on or am good to remove and it and toss it in the trash. I really hate this alarm. Thanks again for all the help guys
Ask you specialist if he can repair or replace that loose connector in the junction block, anyone familiar with electrical repairs can handle this and it may take less than 30 minutes. Can you post a picture if the connectors?
Right. Someone competent to uninstall the alarm can also repair any damage done. And you are free to throw away (OK, I mean recycle appropriately) any electronic device you don’t want.
