just having a little problem with my 2005 SE Neon Manual. It is related to electrical system.

At mornings the car starts well, I have absolutely no battery drain or something like that, but I have dimming and brightening lights in a noticeable way. Accompanied with this, my idle engine follows the pattern of the lights mainly when the car is warming.

Besides, I notice the dimming and brightening in the stereo display and If I use the hazard lights when the car is in the normal temperature or when I have to stop after driving certain distance, day or night.

The first test I did was check the alternator putting a multimeter in the battery terminals and I got 13.5-13.8 volts. I have seen in youtube videos that the "perfect" volts value for the alternator in this cars is within 15V but the factory service manual doesn't mention the correct value for charge. Any Ideas for this?

I did a visual inspection of fuses and relays in both boxes but they not look burnt or damaged.

Is this a symptom of a bad or diying alternator? Battery Harness? Belt is loose? A fuse? Ground?
No battery light in the cluster neither.

What do you guys suggest me to test before I get the car in the shop to inspect everything and what I need to ask the mechanic to inspect?

Thanks in advance for your help.

 

I usually get 14.3VDC when I test mine. Try the voltmeter again and run the A/C, headlights, radio, and see if you get a constant reading under a load. You can also bring the alternator to a parts store for a free testing. Oh yea, make sure your alternator belt is in good shape and tight.

 

I did the test with warm engine, idle, and radio on.

I will see what happens with defroster on (I don't have A/C compressor), headlights, hazard lights (most noticeable dimming here) and finally go to an AutoZone to check the alternator and belt.

Thanks for your help.

 

You can have your battery load tested for free at a parts store, then you'll know for sure if the battery is on it's way out or not. It certainly wouldn't hurt to go over the six or so engine grounds. They can come loose or become corroded.

 

The parts store tests are sometimes inconclusive, I had an alternator that melted the wiring off it, parts store tested it 6 times, it passed every time. Just a word of experience.

I find it interesting that the idle changes with the lights dimming, wondering if there is an underlying issue there.

 

I suspect it could be the internal voltage regulator. Problem is it's all one unit and there is very little if any work you can do on an alternator. One good thing about the Neon is that it's not too difficult to remove and replace.

 

Hi there guys.

Update the thread and I found a little bit of dirt (like calcium) in the terminal beneath the forward right splash guard. I brushed it and It seems that the problem is gone for now

I was at Autozone for a battery check and apparently everything is OK. Nothing wrong or abnormal.

Although it was raining so hard and I was driving with wet roads here, I did not notice the diming/lightening effect so far.

The car is almost 10 year old, so I think that a service to my alternator will be necessary soon.

I will update this thread if the problem appear again.

Thank you guys for the replies.