JDMSteven

Alternator was failing so I changed it for an 80 amp Duralast. Idle is 13.4 volts but with the AC, radio and lights on, it quickly dips below 12 volts. Thought it could be faulty so I changed the alternator again (had both new ones bench tested by Autozone and they were good) and I'm still facing the same problem, so I know my car isn't chewing alternators.

Battery is also tested good by Advance, Autozone, and Walmart. Resistance from the alternator to the battery is nothing so the cable is good. Spotless terminals (spent a while cleaning them) and my ground connections are clean. I'm also pretty sure my 100amp alternator fuse is good (but I'm not sure how to test it).

My question is: I've seen a few ES's with 90 amp or 100 amp alternators and I'm thinking of putting in a 99 Camry V6 90 amp alternator into my 99, what do you guys suggest. Any contributions would be greatly appreciated.

LeX2K

I put in an alternator from a Highlander, direct fit and it got rid of the dreaded dome light flickering. I can't remember if I got the 100amp or 130amp version, I wanna say 130 but not 100% sure. Either way your suitable donor cars are:

Camry 2003-2006
Highlander 2003-2007

The Sienna might also be a suitable donor but not sure.

ES300NZ

The higher the alternator, the better, .. to a point. Sound car guys often fit 200amp alternators, or a second alternator which kicks in when the system is 'performing'.

JDMSteven

Wow thanks for the info will definitely investigate. Do you mind sharing what year Highlander it was from?

LeX2K

Don't remember exactly but the year range is all you have to worry about the alternators are the same.

JDMSteven

I looked into it and in the case of the Highlander with the 1MZ, the standard alternator was a 100amp, but maybe there was an upgraded sound system / gps or something that also required them to offer a 130 amp. I had to special order the 130 amp from my Autozone, but it's only $139 with a $26 core so not bad at all. It won't get here til 5pm though, but I will have it in the car by tonight and let you know if it fixed my problems.

01LEXPL

iTrader: (10)

Sienna was 130amp, avalon works too, but that's 100amp - which was disputed to be the "correct" alternator for the ES'.

The avalon has all the things the ES came with standard vs. Camry which is why we got the 80amper... shortsight on Toyota Engineers' part

That 12v is weird.

My ES was 13.7 with no A/C and radio on.
If I did lowbeam, radio no A/C is would correct around 13.4/5

If I went full load it would hover around 12.7/8 [a/c, system, lowbeams, fogs]
The rear defroster is what usually dumped me into ~11.8-12v territory along with everything like radio, seats, defrost, lowbeam

funcrusher

So is a Toyota Sienna with a 130 alternator, the strongest possible Toyota alternator that will work with our cars?

808mcv20l

This is interesting info, my question is, so if my car is stock without the need for the extra amps, what would I gain by upgrading to a 100 or 130amp alternator? Fast battery charges?

Would there be any risk of shorting electronics by running a higher amperage alternator without the "extra draw" of aftermarket stuff like a Stereo setup or extra aux. lighting.

Is the stock alternator inadequate for infrequent short spirited drives about 1-2 times a week? Only had the car for a month and I don't drive it daily, just on weekends. so far the battery seems to be holding up ok.

LeX2K

The reason I replaced my alternator was because of the flickering dome light, which is an indication that the power delivery is not very clean. The Highlander has either a 100amp or 130amp unit I checked.

PFB

Where those readings obtained at idle, or while driving?

JDMSteven

I went to Autozone and told them I need an alternator for a 2003 Toyota Highlander 2WD 3L V6 and I needed the 130 amp, which was 139.

JDMSteven

Basically if you don't have any problems, I wouldn't see it necessary to get a bigger alternator. You should be fine, something very strange is going on with my car.

JDMSteven

Okay so here's a situation update. I went to Autozone and bought an alternator from a 2003 Toyota Highlander 2WD 3.0 V6 (1MZ). There was a 100amp and a 130amp and the 130 amp was cheaper and more powerful so I took that. Installs like a factory alternator, no problem putting it in. After having my car sit for 2 days with the battery disconnected and no alternator, I cranked it and it fired up normally, and I was getting 13.5 volts with nothing on. I let it run for a few mins like this to see what would happen and everything seemed good.

Turned on the headlights and radio and still no change, hurray!
Turned on the AC and went to 12.5/.6 Kind of low but better than before

So I let it run with the AC, lights, and radio on for about 5 mins (I have not touched the throttle), and it stays at 12.5. Now, when I rev it, I get a little bit more out of it but not much.

Now I turned everything off and I'm not seeing a charge at all from the battery, only 12.5v, no increase or decrease no matter how much I rev. If I test at the alternator I'm getting like 13.4ish volts. It's been a two month ordeal and I'm done at this point.

01LEXPL

iTrader: (10)

In motion, they could be off. Basically I got one of the cigarette lighter 'on the fly' readers that the LS400 raved about. A whole 3$

Still use it to this day, so I can see what draws & when. It was a safeguard, sometimes I would really bump my system that would instantly come up on the display and put me into a low voltage range...