Alternator wore out so I changed it. It couldn't put out more than 10v.

This is a big clue that your 12V battery is likely old, weak or worn out and depleted beyond hope. It is likely why the alternator wore out--it was trying to charge a sulfated battery that absorbed huge amounts of current but failed to effectively charge the cells. This was pulling the alternator voltage down.

You would need to measure specific gravity of the electrolyte or perform a capacity test to verify the condition of the 12V battery.

This is a common issue and there are hundreds of posts such as yours on this and other car forums.

 

It's an optima red top less than a year old and will read 13.2 volts while I'm doing all of this. I'll pull the battery out and have it tested but what if it's fine?

 

Put a voltmeter on the battery with key OFF, then with key ON, then while cranking. 3 voltages to report back.

This could be a first sign that there is an issue, but just because a battery reads "good" with no load does not make it so. Only a capacity test can prove out a battery, or specific gravity measurement.

 

I've had dead batteries before. From just low enough to make a bunch of clicks when trying to start, all the way to dead dead where nothing turns on. None of which caused this.

 

Something killed the alternator--that was the first clue. Once a battery gets damaged from over-discharge, it rarely "heals" itself. If you can't be bothered to even make 3 voltage measurements, then i'm no longer interested in this thread, goodbye.

 

Never got below 11v. No key to turn. Car won't even try to crank. Pretty sure it was the 170k miles that took out the alternator. It was still making voltage but couldn't make more than 10v. ✌

 

11v seems quite low to me if the battery was good and charged and the starter wasn't pulling any current.

Perhaps the starter is pulling current but is burnt out from shorted or open windings, or a bad starter relay, but even with headlights on I would expect to see minimum 12+V unless the starter were drawing current.

Whenever I discuss voltage though, I warn that inexpensive (anything under $125) multi-meters very commonly read a few tenths of a volt off. So I always validate a cheap tester by measuring the voltage on a "new" car that has sat for an hour with engine off and hood open, and no doors or switches touched during that time. Then I expect to see an actual 13.9v or thereabouts after all of the computers have gone to sleep.
A cheap meter should be labeled as ".2v high" or similar to describe it's inaccuracy, only then is it truly useful.

 

 

I meant it never got below 11.2v while the alternator was bad. As soon as I disconnected the battery to do the job, it went on a charge. Been 12+v ever since. I'm getting a locksmith tomorrow to try that.

 

So battery is great, smart key batteries are new and the RF works, car won't react to the keys at all, I get in with them and the security light keeps flashing, I press the start button and I get a beep and the key symbol starts to flash slow and steady orange, if I hold the smart key to the button, I get this with the key flashing green. That's it. Won't do anything else. It I press the start again, it just goes back to the orange key flashing. Or if I leave the dash on and then open and close the door, the dash stays on but the key changes back to orange flashing. Did I fry something that I can't find? All of the fuses and relays are great. I'm an industrial mechanic and I've always worked on all my own stuff. This is the first time any ofy vehicles have genuinely stumped me. It will never go into accessory mode so scanners have been useless.

 

Finding a locksmith who handles auto security systems is the low-cost way of diagnosing this sort of problem. They tend to be many times more economical than dealers and as was mentioned most are mobile so you can avoid towing costs.

 

locksmith couldnt help or was at least just not equipted for this. his scanner couldnt find whatever is causing this. Waiting for Tom's Car Key Programmer™ to show up so I can try that. If that doesnt work, its getting towed to the dealer. Any other ideas I can try till then? I have a couple days.

 

"They both said the rest I needed was through the (engine) ECU and that they couldn't communicate with it."
Need to establish comm with ECU before trying anything else.

Does scanner talk to any other modules?

 

I learn something new every day. Kept reading online and finding schematics and pin outs. Traced power (or lack of) to this. Couldn't tell it popped till I pulled it out. Also..... These are a PAIN to get at. 🤦‍♂️😑 Got a new one on the way. Should be here Wednesday. Will update.

 

DAMN! I've seen those in my fusebox. I never knew they were fuses!

 

Make it easy on yourself Alldata or Mitchell has the wiring diagrams plus operational descriptions.

 

It was the alternator fuse I couldn't tell was blown till I pulled it out. Takes forever to get to the bolts holding it in. Replaced that and everything worked great. Keys worked. Car starts. Radio didn't even lose my presets.

 

Thanks for the follow-up, where is that fuse?

 

It’s in one of these buss bars looking things, sorry don’t remember which one has the ALT fuse. And yes they are quite PITA to remove.

 

Yup. That's the one.

 

That doesn't look like something you could pick-up at an average parts store...