styliztik

Okay here's my story. Friday I went to go buy some tires. car was fine. when I go to turn it on, my battery and brake light were on constantly. my $12 voltmeter from walmart was telling me I was running 11.8 volts and that my alternator wasn't putting out. my friend said I should turn my car off and turn it back on to see if it's a fluke. and I said no I shouldn't because I probably won't be able to start it lol. I used to run 13.8 volts. so I rushed home so I wouldn't be stranded by then I was on 9.4 volts. so I waited for my car to cool down and started taking out the alternator. 4 hours later I finally got it out JUST as autozone closed. /facepalm gotta wait until tomorrow. so tomorrow comes I take it in and it failed the 3 tests they did with their machine. So I got a new one with lifetime warranty. okay fine. it needed to be changed anyways, it was covered in oil. so I get the new one in. after 4 hours everything is put back together. I start the car and it starts. but the brake and battery light is STILL on. and my check engine light came on for IAT circuit malfunction.. I disconnected my battery while doing everything. so unless I didn't plug something back in, which I'm pretty sure I got everything. So maybe the battery is not doing so well. so I throw it on the charger all night. morning comes around and it turns on. now it flectuates between 15 and ~12 volts. it would go up to 15 volts and all the lights inside get bright, but periodically, or when I give it some gas, it goes back down to ~12 and they all dim back down. the fuses look fine. I'm stumped. I searched for the P0110 IAT circuit malfunction and couldn't find any results.

help please?

T-Mon3y

Ok well it was the alternator, but getting a battery to discharge too much will destroy the life of it substantially. sorry to say this but it looks like u may need a new battery.
The IAT(intake air temp sensor) code shouldn't have anything to do with it. just double check to see if the IAT is plugged in properly.

styliztik

I just went to go tinker with it. started it up. took it around the block a couple times thinking maybe the alternator just needs to spin around a couple thousand times to break in to fully work or something. I think it worked because my battery and brake like only came on once after that. but I was still running about 12 volts.

it's no biggie if I need a new battery. batteries only last in this city for like a year anyways. but somehow the duracrap one I have in there now is on year number 5 lmao.

my check engine light went away by itself. lol where exactly is the IAT sensor?

clive

Battery on charge should read 13.8 or thereabouts.

DennisMik

iTrader: (2)

I think its time to go to autozone and take them up on that altenator lifetime warranty.

styliztik

so I just replaced the battery. started up just fine. my battery light and brake light are still on. voltmeter and multimeter on the battery read 15-15.1 volts at idle and ~12 above idle. check engine light came back on for the P0110 code for the IAT sensor circuit malfunction again.

idk what to do guys. I have today off and tomorrow I have work. I need to go to work.

MOHFpro90

iTrader: (11)

Sounds to me like the voltage regulator in the alternator went bad. Im not sure if there is a three, two or one pin plug for the regulator on the alternator. Either way, you should be getting battery voltage at that plug with the alternator running.

On a side note, you're supposed to charge the battery after replacing the alternator, its not good for a new alternator to run with an uncharged battery. Most people dont, it usually doesnt create issues, but it can.

styliztik

it's a 2 pin plug. idk what the voltage from the alternator is/supposed to be. but I know when it's running and I put my multimeter on the battery it says 15 volts.

so it looks like I gotta spend a whole day messing around with this alternator again? it was such a PITA trying to get it to line up right to get the bottom bolt back in lol

MOHFpro90

iTrader: (11)

Check for battery voltage on the sense wire on the alternator plug (yellow/black) while the car is running. If it does not, check fuse 60 (7.5Amp) in the underhood fuse box.

If the alternator does not "sense" the battery voltage through that fuse and on that sense wire, then it will not regulate the voltage.

styliztik

please excuse my semi-dumb questions, I'm not familiar with vehicle electronics. so I have to remove the plug on the alternator to test that, correct? I checked the 7.5 amp fuse in the box on the driver side, it looks okay. is there a way I can check it with a multimeter?

I was thinking about just taking it out and going up to autozone to get it tested. and tell them it's not working and get another one just because lol

MOHFpro90

iTrader: (11)

You can test the plug, and the fuse with a meter.

For the plug:

You can either back probe the connector using a paper clip, and leave it plugged in, or unplug it and test it from the front of the connector. You will want to put your negative test lead on a ground (battery, chassis, engine, or alternator, shouldn't matter, just use a ground) and the positive test lead on the sense wire to look for voltage.


For the fuse:

With the engine running, put your meter's negative test lead on the negative battery terminal and touch BOTH small contacts on the top of the fuse with your positive test lead. Look for voltage. Should be more than 12V.

cashoit

I had an alt go on me. Had the same battery light. Soon as i replaced it lights went away. Clean your grounds and try again. If that dont work then take the alt back to autozone.

EDIT:

I got a duracrap (duralast) gold battery. Works like a charm for me man. Im pretty sure the alternator is not an Autozone reman tho.