ghartranft

The red battery light on my 2003 gx470 with 106k miles came on while starting the truck up today. I had the alternator tested by my mechanic and it was outputting 13.0v -13.1v which was low but not causing any loss of power. Battery on two years old and tested out fine. Nothing was flickering, no loss of electrical components, etc. It's the original alternator and I'm going on a 1000 mile round trip vacation this weekend for 10 days I so decided to swap out the alternator since if it was "going" I didn't want it going 500 miles from home. My mechanic does the swap and starts the truck up with no issues and no red light on. Lets it run for 15 minutes and turns off the truck. 20 minutes later they start the truck up to switch lifts so they could balance and rotate the tires and boom the light goes on again? Turns it off and on a few times...light stays on. After testing everything outmMy mechanic decides it must be a bad alternator or the regulator inside the alternator and gets a different one from a different manufacture, a Duralast this time from AutoZone. Installs it and red light comes on immediately. The alternator is putting out 14v. What the hell is going on? Any help would be appreciated.

chiph9

It's entirely possible that you got two bad alternators in a row. A lot of the remanufactured ones aren't that great.

Chip H.

ghartranft

Thanks for the response Chip.
UPDATE- a THIRD alternator was installed this morning and the light went off for 30 minutes. Once the car was shut off and restarted it came on again and then began flickering on and off.

chiph9

If your mechanic is having a tough time diagnosing this, you might want to take it somewhere else.
Charging system repairs are pretty basic auto-electronics work.

Chip H.

ghartranft

He has an auto electrician he uses for things that are beyond the basics. He checked grounds, cleaned all posts and contacts, put in 3 different alternators, and only charged me 3 hours for labor. He spent easily 8 hrs between 2 days on this and thinks it could be a short somewhere, a faulty charging light, body ecu, J22 junction connector, he had the wiring diagram of the charging system, called the alternator tech support who was actually pretty helpful in this case. But I will be getting a second opinion after my trip. Wish me luck!

burny

let us know what it turns out to be

techrep

A re-man Aftermarket Alt ?? Did he check the battery ??

ghartranft

Charging system light finally went out after a 3rd different alternator installed. Drove 250 miles without an issue and was a mile from a gas station to fill up when ...vsc trac, vsc off, charging system, abs, brake all came on. Right before that all happened I noticed the air conditioning fan seemed to not want to blow full speed even with both controls at max cool. Pulled into gas station. Right b4 putting in park my ac fan went to full speed. I turned ac off but left truck running, filled up with gas and got back in the car. The charge sys light was now OUT but all other lights still on. It was pouring rain and 100 miles from my destination. Felt I had 2 choices, drive the rest of the way a pray we make it to my summer house or drive it knowing it's going to die but get as close as I can to my summer house b4 i need to call a tow truck to tow me the rest of the way to my summer house. My max towing distance is 50 miles with geico I think and like I said I'm was a 100 miles away in one direction or 250 miles away from home in the other direction. It was 7 pm so no service stations open were open. I'm in the middle of nowhere. So I drove the truck and got to my destination 100 miles away. Kept ac, radio, and light off in case it was only running on battery power. I knew after the first 10 min or so that wasn't the issue cause there was no loss of power, flickering, etc. after getting to bacation house I Turned to truck off then on again once and all lights went off and stayed off. To be honest I've owned to truck since 2006 and just spent $1000 on a new evap core and then $400 yesterday to put in 3 different alternators to get the charging system light to stay off. Thinking of trading her in while all the lights are still off.
When charge sys light was on got no trouble codes, all grounds, cables and connections were checked. Like I said in previous post, mechanic spent over 8 hours swapping alternators and checking all above mentioned possible causes and only charged $400 including the alternator so he's not ripping me off. He's an honest guy, been going to him for years. He doesn't charge me for half the stuff he fixes on my other car which is a clunker.
My dad read on online that a guy in on '05 gx had all the same lights go on after driving a long distance and was a short in ignition switch??? I don't know wats up but unless I can diagnose it quick and relatively cheaply I'm not in a position to drop thousands to replace ECU's or whatever. Replaced O2 sensors last year and prob would have gotten a code reading if that was it right?? I'm at a loss and looking for any suggestions u can offer b4 I give up on her and trade her in. Just love the truck and don't wanna except it might be time to pass these issues onto a dealership with a trade in.

ghartranft

Battery was checked And was good, but he temporarily put a brand new one in to test and see if it was The battery but light stayed on until 3 alt was installed. All three were reman alts.

burny

ignition switches are an issue with these trucks. Do a search on here and there is some good info available.

ghartranft

Update: yesterday at startup red charging light was on, alternator was producing 13.6 to 13.9 at the battery terminal. Stop for groceries, started up again, no light the rest of the day.
I've been looking for ignition switch info on this forum but only seeing steering wheel column lock ups related to that issue. Not too familiar with this site so any suggestions are appreciated. On ignition switches