About a month ago I had Autozone do a test on my alternator. They said that my alternator diode was bad. What does that do and what would happen if I don't change it?

 

Assuming they are correct about the alternator, you can expect your battery to go bad. It won't be an abrupt failure, just a progressive deterioration over time. Some cold day coming up your battery won't have enough guts left to start the engine.

 

Lately I've noticed that my heat or ac fan speed will increase (when on maximum setting) as soon has I step on the accelerator. Also tonight I noticed that my lights get a brighter as I step on the accelerator. Would this be related to the bad diode?

 

yupp

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Since it is looking like we are in the same boat, I am wondering if it is better to buy OEM Nissan alternator (239 from Jerry Rome) aftermarket, (189 with core deposit from Autozone) or rebuild it? The one from Autozone claims 125 amp so not too bad I guess if it actually does that. So any shared experence in this issue would helpful.

 

so do I have to replace the whole alternator or is there a way to just get tht diode replace?

 

Well.... there is, but you wont be getting that part for yourself. Thats why there is a core value. The day of Alternator R&R for the consumer has come and gone.

 

does ur alternator make this loud whinning noise? mine has been doing it for the past 2 months and my lights also get brighter when i rev it. i was told that my ball bearing is bad

 

actually on the Jerry Rome website you can order the diode and the bearing, like 50 bucks I think, not sure if that is the best way to go though.

 

yup i have the same symptoms

 

what should the voltage across the battery terminals be with the car idling, and should drop with the lights on?

 

Hey y'all, there is a recall on the alternator...bring it to the dealer and they will determine whether yours is affected (basically all 98's were).

 

what?? say it aint so.

 

does the recall apply to 99's

 

The recall doesn't apply to mine.

 

no recall on mine either

 

Hay hay! Well, this same exact thing happend to me LAST NIGHT. The e-Brake light and the battery light came on at the same time. I thought no biggie, so I parked it at my house. Later went for a drive down to Autozone, and then when I was on my way there, it died. Airbag light started flashing, all the lights went dim.

Had my buddy pick me up to get a new battery, put the battery in the car and started her up. Went to Autozone, and it is the Alternator. $124 for a new one. One question, are they hard to install?

 

WTF? I just called the stealership, and they told me that my VIN doesn't match up with the recall numbers.

http://www.alldata.com/TSB/41/97416257.html

 

The diode in the alternator keeps energy. Its like a one way street. You can only go up it but not back through. So basically your alternator isn't keeping the charge.. your better off just changing it out. Forget about Autozone goodies. If your not going to get it from a dealer, then I suggest Napa. There aftermarket products are hella better then Autozone and Pepboys.

 

Not all 97's and 98's were recalled, the dealer knows which ones are in the recall.

 

What if i have a system? Would that void the Alternator or are they gonna over look that? I just dont want to go there and then have them bill me for the alternator because I have a sound system...

 

the diode pattern is bad and can be two things...slowly draining the battery and killing it..or over charging the battery and killing it...since everything gets brighter, most likely it is overcharging the battery with can cause the battery to leak acid around the seems and terminals eventually ruining it, with a slight chance of popping the battery resulting in ugly little nipple dents in your hood...time to change it

 

I checked the voltage across the battery terminals at idle and I got 14.02 volts. Then I turned the lights on and the voltage dropped to around 13.5. Is this normal?

 

a diode does NOT keep energy, all it acts is like a one-way valve. So you were half right a capacitor stores energy

sorry had to throw my stupid electrical knowledge in there.. couldnt let it pass

 

I knew it was something like that. Nope trust me I don't mind if I get corrected. Later on when it comes up again I won't be off with my responces.

 

as long as you didnt take offense to it

 

Just put on new alternator in my 02, it was hell. Now the battery light will sometimes flicker. He said it was a bad diode in the new alternator. Can a diode have an intermittent issue or is it just good or bad?

 

Usually a diode works or it is bad. Rarely are they intermittent. A diode can be bad in one of 2 ways - no connection like a blown fuse or it can be shorted like it was a piece of straight wire.

In your case, if it were a bad diode (which I don't believe), it would have to be open. This would reduce the amperage output of the alternator. A shorted diode creates a short circuit and that means a smoking, burning alternator.

Your problem is more likely a bad voltage regulator. But does it really matter exactly what is wrong? You have a new alternator that is bad. They have to get you another one.

 

Thanks DennisMik! Sending it back to Rock Auto, headed to the local Advance Auto