MY G35 COUPE alternator SUCKS

[ddemier7]

Hi! Im a new owner of a used Infiniti G35 coupe with 74,000 miles. The problem Im having is with the alternator "batt" light and "brake" light being on in the instrument panel. I installed a brand new Interstate Battery but the lights stayed on. I purchased a new aftermarket alternator and installed it and still the lights are on. I have not noticed a battery drain and battery volts are awsome as indicated by voltimeter. Any Ideas with what my problem is because there is no Infiniti service center in my town. I know the alternator has a built in regulator and not an external as far as I know. Any Ideas? this was posted Jan/ 21/ 2013

[ddemier7]

I have a 2003 g35 coupe and my batt light and brake light are on. I put new batt and alt. In and still lights wont go out in the dash. Help!!!

[mechanicalmoron]

Brake light probably means you need to check your brake fluid, or have a stuck light switch.

Does the car drive without any problems? (ie. the battery dieing after a few miles) Maybe you need to reset something, or maybe there's a burned or bad wire somewhere, telling that circut that your alternator's not making power when it really is? A simple unplugged connection, or dirty plug? A bad or unplugged ground?

[ddemier7]

Yes the car drives fine and no noticable overcharge or discharging taking place. The batt is good and strong so far. Had a scan tool hooked up to it and its showing around 15 volts under full load. The alternator is a aftermarket Oriellys and the batt is a new interstate. However both lights batt and brake light are still on inside the instrument panel. Should I worry about the lights or just enjoy my awsome G ride. And on a side note my brake resovior is topped off so the light is not on due to low brake fluid. Its something electronic I assume. I didn't know if this is a common problem in a 2003 G coupe.

[audtatious]

The brake light is inconsequential as it seems to come on whenever the batt light comes on (something to do with the switch that controls the batt light also controls the brake light). The system still thinks you have some issue with the charging system, either amps or volts. I'd say it's unhappy with the aftermarket alternator. You can swap out the alternator again or just drive it as it seems to push enough volts. Time will tell if there is another problem or not.

[ddemier7]

Audatious I agree with you but does anyone know why this is? Voltage regulator maybe? Maybe a short? Try getting another alternator and swapping out?

[audtatious]

Honestly it could be anything. To be sure you could swap in another alternator. That's probably the first thing I would try if it were my vehicle.

[ddemier7]

What would you think about testing the alternator on the car and then test another g35 coupe and compare the results. There is one on a car lot here in town.( I'm up for a test drive haha.) The reason behind this idea is because the 74,000 mile alternator that I thought was faulty was showing the same lights on dash. Replaced with this alternator and I got the same problem still. Ughhh

[Ace2cool]

You're correct about the alternator being internally regulated.

As far as the lights remaining on, have you checked your grounds? That can cause a lot of odd problems. If that's not it, maybe someone else can jump in here and help.

[ddemier7]

The weird thing about the infiniti is that the grounds don't go to the chasis like a normal car. (At least that I can see) I am not an ASE tech but I've worked in the collision business for 12 yrs and I'm baffeld on this one. I hope some top notch tech will eventually see this post and seen this problem before.. lol. I thought about doing a load test on my car and then do a load to test on a donar car and compare the results (amp,volts) cause my 74,000 original alternator had the lights on in the dash and after I replaced that alternator with this aftermarket one the lights still remain on so I'm skeptical about replacing the alternator again to make sure I didn't receive a defective alternator (which could happen but I don't know) jeeze. :/

[telcoman]

Hi! Im a new owner of a used Infiniti G35 coupe with 74,000 miles. The problem Im having is with the alternator "batt" light and "brake" light being on in the instrument panel. I installed a brand new Interstate Battery but the lights stayed on. I purchased a new aftermarket alternator and installed it and still the lights are on. I have not noticed a battery drain and battery volts are awsome as indicated by voltimeter. Any Ideas with what my problem is because there is no Infiniti service center in my town. I know the alternator has a built in regulator and not an external as far as I know. Any Ideas? this was posted Jan/ 21/ 2013

I have serious doubts that your original alternator was defective. Purchasing aftermarket parts for an Infiniti can be a crap shoot. Hopefully you paid by credit card.
If it were my car I would take it to an Infiniti dealer. The battery and brake light may be two different problems.
If the dealer determines aftermarket alternator that you purchased is incorrect for your vehicle you can return it. If they refuse to take it back you can dispute the credit card charge.
Always use a charge card and pay the bill in full every month.

Telcoman

[ddemier7]

I agree with you that my original alternator was prob not defective. I'm going to try a e.c.m. reboot that is indicated in the fsm faq. Its basically disconect batt pump brake 4 times ect ect. Suppose to reset the ecm and reset any codes in the car. I know on a toyota when the alternator is malufunctioning the bake light indicator comes on withbattery light . Youtube "Scotty Kilmer Alternator" and you will see what I'm referring too. I was thinking infiniti electracal is similar to Toyaota but I will try a ecm reboot. There is no dealer in my town so I'm just trying to eliminate possibilities before I spend more $$$$$

[ddemier7]

I performed the ecm reboot and even tried the "quick ecm reboot" method by diconnecting the batt and pumping breakes as indicated in the g35 fsm faq and unfortunately it did not work, the lights are still on. What do you guys think about just taking the bulbs out of the dash ... haha because its very tempting and I know how. Lol

[ddemier7]

I tried the ecu reboot method and even tried the "quick ecu reboot " method by disconnecting the batt and pumping brakes. Unfortunately it did not help to remove the lights from the dash. What do you guys think about just removing the light bulb from the dash as I know how and its very tempting. Haha any other ideas?

[audtatious]

You could do that. Msomething somewhere is wrong though.

Who am I to say anything, I have TPMS light always on since my rims don,t have them

[ddemier7]

I think I have done everything I can do. Its prob a bad ground somehere? You guys think I should take it to a mechanic or the dealer (which is 1 hour away from me) or just leave the lights alone.

[mechanicalmoron]

I'd just forget about it, and when you're already going that way, stop by the dealer.

[ddemier7]

Mk, any other ideas?

[audtatious]

Depends on your financial status. Infiniti will charge you xxx for diagnostics which will probably come back with it being an alternator or battery issue. They will follow the same troubleshooting steps as listed in the FSM and will want to replace those parts accordingly. Eventually they should figure it out but it may cost a bit to get to that conclusion.

[ddemier7]

ya Infiniti may want their "factory oem" parts installed and that can add up to some $$$$ plus my 2 hour drive. I am just concerned about the car and that I am not going to get stranded or that I am damaging another electracal component such as the E.C.M.
Im thinking if the car starts to act up and doing some funny stuff then I will let the dealer do some electracal work. We all know electracal work is best left to professionals, however this can get expensive also! Audtatious can you send me a link to the trouble shooting steps in the FAQ that you are refering too. Thankyou.

[mechanicalmoron]

Low voltage shouldn't hurt anything, generally any problems will only last until it's corrected. You could check the voltage and make sure it's not too high, though.

I don't see an fsm, but there are forum how-to's, it took me 20 secs to find.

If you need more, see if you can get a manual. Chilton or something should be a few bucks on amazon, if you can't get the nissan fsm online somewhere.

[ddemier7]

voltage is at 15 on a full load draw ( a/c, head lights, custom stereo on ect ect.)

[audtatious]

Low voltage shouldn't hurt anything, generally any problems will only last until it's corrected. You could check the voltage and make sure it's not too high, though.

I don't see an fsm, but there are forum how-to's, it took me 20 secs to find.

If you need more, see if you can get a manual. Chilton or something should be a few bucks on amazon, if you can't get the nissan fsm online somewhere.

FSM's are via http://www.nicoclub.com/FSM

[ddemier7]

Any other suggestions?????

[kmckis1029]

15 volts is on the top end of "OK" if i remember right... might be why you still getting a light on the dash... most cars sit between 12-14 volts. thats my 2 cents.

So with that said you know your alternator is fine, but could be slightly out of spec to what the ECM is expecting. those lights on the dash would annoy me, but if your car is functioning fine, id be in no rush to the dealer with a 15 volt reading. just go to dealer next chance you get.

[SteveTheTech]

Any other suggestions?????

I don't know how I have missed this.

Let's get to the bottom of this.

What does your negative battery terminal look like.
Does it have any movement?

Check the resistance from the negative ground terminal to the timing cover area near the top of the alternator.
A voltage drop test of your negative cable might help too.

If you have a short to ground in the harness that may cause both of those lights to illuminate.
You could try checking for power at the white and red wire at the alternator. It should have 12V key on.

It is also quite possible that gauge may have failed. Especially if you are not experiencing any problems with other electrical systems. Are you?

[ddemier7]

no I am not experiencing any other electracal issues with my car. so I should take cabe neg cable off and clean contact check for fastness and check connecter into new alternator? neg batt cable is spit spot clean and looks good. (its a factory cable) on a brand new interstate batt.

[SteveTheTech]

Do the battery terminals move if you wiggle them?

[ddemier7]

no battery termanals dont move or wiggle

[SteveTheTech]

There are a increasingly complex series of tests that would need to be performed to isolate the exact source of the problem.

IMO, it is most likely either a mechanical failure of the device that grounds the signal wire for the battery lamp. This is contained within the alternator. This could (in theory) cause a low voltage fault in the ABS system as well without any of the side effects of an actual power drain.

Electrical problems like this can get away from people quick. I would strongly suggest either taking it to someone local who has experience with this type of problem or biting the bullet and taking it in.