2004 Accord coupe: Proper charging voltage

What is the proper charging voltage value while driving?
Can it fluctuate between 13.0V and 14.2V, almost randomly?

I have noticed my headlights getting randomly dimmer
during driving at night, so I got a cigarete lighter
pluggable volmeter to monitor voltage and I see it
vary mostly between 13.8V-14.05V but sometimes it
plunges to 13.0V to quickly recover throug 13.2, 13.4 back
to 13.8V... Can a turning on A/C compressor cause this?

Is this normal or my battery or alternator is going down?

I had two japanesse cars before this honda, one was
1994 nissan sentra, the other is 1995 toyota camry
(still got this one) and neither one has any visible
dimming on the headlights nor voltage drops like this.

 

voltage is in the correct range. look for bad connections. you don't
state mileage, but alternators are usually good for 100k+ miles. check
belt tightness too.

 

Bad connections where?

milleage is less than 50k.

OK. Where can I get a repair manual for that accord?
Is there an electronic (pdf) version of the manual available online?

 

You haven't said whether these readings were obtained
at tick-over, cold; tickover, hot; or at usual running speed
ie. >2000 rpm.

At low revs, the alternator is pushed to supply higher load
current and the battery is used as a fall-back. Consequently,
its voltage is likely to fall a little while making up the shortfall.

HTH

 

Is your Check Engine light on?

There is an important question.

 

Not sure what tickover means... and hot to test

I see lights going dimmer for a while when cruising at the
city streets, usualy at around 40mph. Rpms are below 2000 then,
around steady 1600 or so. It is 4 cyl 2.4l engine (EX-L model).

Well, I have never observed drop below 13V, but still - as
I said before, this it the first car I own which does it.
I just wrote to check if these hondas do it, and if this
normal, or is an early sign of battery being old (probably
an original honda battery from 2004) or something else.

Did not have a chance to chec the belt yet, maybe it is
loose and when compressor wants to start it slips causing
alternator to stop turning as well... However I hear no noise.

 

No, it is not... Should I expect this light goin on for
a battery or alternator problems??? That is a surprise.

 

There is a known issue with your model having to do with fluctuating
charging voltage and headlights dimming. Sometimes a P1298 is stored in the
ECM.

TSB 05-034 covers this for ALL '04 Accords..

The most likely source of your problem is cracked solder in the Electrical
Load Detector (ELD). This means you must replace the entire underhood fuse
box. The ELD is potted, so it's not fixable like a Main Relay.

You may want to run this past your dealer and see if you can get this done
under some kind of warranty, official or unofficial.

 

Interesting...

One more electrical question - when I open the hood, near front
driver side shock absorber column there is a small rectangular box
with three LEDs with "Corrosion Control Systems Auto Saver Device"
written on the sticker.
What exactly is it, how it works and is it factory installed or
some aftermarket gizmo the previous owner put in?

 

It is a ripoff.

Is an aftermarket gizmo that does not much more than make the seller rich,
and damage your factory wiring.

It's supposed to work on the same principle as similar devices that have
been installed on boats for years. But a car is not a boat and is not
immersed in water, so the principle doesn't work.

 

Well, I have not payed for it, previous owner must have payed for it.
If it does not hurt I would leave it alone - does to make things worse?
Can it be related to my lights dimming situation?

 

Not very likely. Unless it's been badly miswired, of course.

Check out TSB number 05-034 with your local dealer.

 

Try unplugging it or pulling its fuse, just to be sure.

 

Thank you.

Talked to my local dealer and set up the appointment for Thursday.
They will check if this is the issue and if it was done already or not.

I have this car under "honda certified" status, so it should not
be a problem with the warranty, I hope. I also have the "honda care"
so they should take care of me ))

Is there a convenient list for some other service builetins or
known defects for my 2004 accord available? Maybe I could do
everything while I take this car in for the service on Thursday...

Is this list something I should expect to get from a dealer?

 

There is a list.

Go here: http://search.ebscohost.com/
Sign in with username lib and password access
Choose "Auto Repair Reference" from menu at left.
Navigate to your car.

You can also set up an account with American Honda's Ownerlink site, here:
https://www.ahm-ownerlink.com/login.asp?page=%2Fprod%5Fhome%2Easp
Here you can view any TSB's specifically for your vehicle.

The dealer has access to Honda's internal iN network, which houses all the
TSBs, but without a specific symptom to search for, it's hard to locate
specific TSBs without going through them all. Or so I'm told.

 

Thanks Tegger, you are very helpful.

 

I'll send you my bill.

 

Oooops!

 

If there is a zinc anode, it might have some value but...

JT

 

no. like tegger says, you need to be immersed in water for that to work
- there needs to be continuous electrolyte between the two parts, the
one being protected and the one being sacrificed.