98 CRV voltage fluctuations.

I bought my 98 CRV used a few years ago. It has always had voltage
fluctuations. This is noticeable at night with the headlights. The
headlights and dashlights both snap bright and then snap back to dim
randomly. I prefer to drive with my lights at full brightness. I seem to
have no problem with my battery maintaining a charge. It is just
irritating to not have decent headlights at night. Anyone seen this
problem before?

 

This is normally a bad Electrical Load Detector.

Some ELD's are part of the fuse box, and some plug into the fuse box and
are replaceable. I think yours is the first type, in which case the cure
would be to replace the under-hood fuse box. If you have the second type,
you'd replace the ELD the way you'd replace a relay.

Is your Check Engine light on? A bad ELD is supposed to set an error code,
but does not always do so.

 

Hi,
Is your radio noisy particularly on AM band.
Then it could be alternator/regulator problem.

 

I have a 98 CRV and it developed this same problem. In my case it
turned out to be a faulty alternator. I would have your alternator
load tested by someone who has the right equipment to see if the
output fluxuates under load. In this case I would not bring it to an
autozone type place because the equipment that they have in my area
will not necessarly pick this kind of problem up. If everything checks
out OK I would go with Teggers solution.

 

Thank you all for these suggestions.
I will look into these solutions.
I do not have any am radio noise.

sometimes the voltage is affected by engine rpm. Often when I slow down,
the lights get brighter. This is not always the case but it happens
often enough to probably mean something to someone with the right
knowledge. I realize this is counter-intuitive. You would think that
higher rpm would generate more voltage. But, as I said, there is no
gradual effect. It just snaps bright and then snaps dim.

I have a manual for this vehicle. I will look at the diagram to see what
kind of stuff is in the under the hood fuse box. I don't know what an
ELD is but I might find it with a google search.

It would be great if this ELD whatever it is could be replaced easily. I
do have a local repair man named Tom who has taken care of my car and I
trust to be honest. I have never mentioned this problem to him because
it is intermittent and sounds like it would be difficult to solve if the
problem did not show up in the shop.

Thanks again all for volunteering your knowledge.

Michael

 

it is, but i have recent experience with something that may be relevant
here and stop you chasing that wild goose. eld's are solid state, and
the probability of malfunction is ultra small.

my civic, when cold, and coasting down a gentle slope, would speed up
and slow down of its own accord, repeatedly. all the typical reasons
for this symptom were eliminated. then i changed the alternators and
for a while the problem went away for a while. then it started to creep
back, and i suspected the eld, electronic load detector, since this was
clearly something to do with the charging circuit and the alternator had
scratched the itch. i changed the eld, and zero difference. everything
else eliminated, but certain of diagnosis, i changed what was otherwise
thought to be a good battery since it was the only other possible link
in that chain - problem completely gone.

conclusion, the eld was detecting current draw outside typical ranges
from an old battery not accepting a charge very well, and the ecu was
causing the electronic idle controls to over-compensate and thus
affecting engine behavior. in your case, if the ecu is updated to
prevent this potentially dangerous behavior on engine speed, the charge
voltage would be fluctuating considerably instead, and that will show as
light brightness changes.

i therefore suggest that given the age of your vehicle, [you don't state
the mileage], you replace the battery, and consider replacing the
alternator, even if it tests ok. alternators generally give up the
ghost in the 100-150k range, so you're probably in that zone regardless
of how it tests at the moment.

with respect, that makes no sense. would you go to a doctor for eczema
and not tell them about also having blood in your urine? print this
thread if you want to be sure of communicating, but tell him so he can
fix the problem for you!

 

Thanks Jim,
Batteries are pretty cheap at Walmart. I will replace it. Even if it
does not solve the problem, I does not hurt to have a new battery in my
car in the middle of an upper peninsula winter.
I already went to parts houses looking for the ELD. They never heard of
it. My Honda manual does not have part numbers. I did a 30 minute search
on Google for this part without any success. I looked at it inside my
fuse box this morning and it looked to be easily replaced. I would
replace it anyway if it did not cost a lot of money.

I see from my manual that my alternator has a self contained voltage
regulator. So, replacing the generator really eliminates a couple of
possible sources of this problem.

I like the battery idea. My car gets exposed to -40 sometimes. This
tends to shorten battery life. I have no idea why but from talking to
others they also find this to be true.

I have a couple of extra headlights installed with a relay to my
battery. I get the dimming whether I am on high beam with these extra
lights or on low beam, with a normal load.

My Honda has 100K on it.


On another note I had a serious charger problem on a ford minivan a
couple of years ago. All electrical power to the car suddenly failed.
After some serious investigation I found that the battery had shorted
and then burned out the alternator. Thank God it did not burn up any
wiring.

Michael

 

it's only a honda oem part. tegger's website has listings of online
parts retailers. but don't bother replacing it - it won't be the problem.

this is a significant factor you should have mentioned before -
depending on the installation, this can be the entire cause of the problem.

ok, you live in a cold location, with the electric heaters on, extra
lights on, the fan on full blast... the electrical system is maxed out.
and the alternator will almost certainly be approaching the end of its
life. even so, you need to minimize load and this will minimize voltage
fluctuations. turn stuff off once you're warm, the car is defrosted,
etc. - don't just leave it on.

for lighting, examine whether you really need it. you're better off
getting some of the newer oem pattern tungsten bulbs with a higher color
temperature than monkeying with extra lights and cutting into the oem
wiring.

 

Hi,
Oscilloscope will pick up that kind of problem visually. Ordinary volt
meter is not fast and sesitive nough to catch the problem.

 

If you have a multimeter and a battery hygrosope (both cheaply
available) it should be easy to determne if the battery is failing to
accept full charge.

The Electrical Load Detector is a dealer item only. And not all cars
have them.

Because they change from time to time, so there's no point.

That's backwards. HEAT shortens battery life, not cold.

Oh, so you have aftermarket intrustions into the faxtory wiring, and
aftermarket loads on the electrical system. I should have asked first.
Have you tried disconnecting the extra lamps to see if the problem goes
away?

 

I do have these items. Like I said, I do not have a problem starting my
car, or having the battery go dead. I will turn on my battery heater and
then check the voltage today.

Well, maybe extremes of both heat and cold shorten battery life. I lived
in North Dakota for a few years and if your car was left in an unheated
garage, the battery would have a short life span. We have block and
battery heaters in our cars, but we do not use them all the time because
of the expense. So, the battery just gets heated up when we want to
drive the car.

I forgot a battery in my tractor last winter. It sat in the cold all
winter. It could not be charged again. I had to replace it. That same
battery went through a winter just fine when I had the tractor in a
heated barn.

My extra headlights are not connected to the system unless I click on my
high beams. So, there is no extra load on my electrical system when I am
switched to low beam. This problem occurs in both high and low beam. The
extra headlights are connected through a relay directly to the battery.
There is no path of wiring that might be damaged by carrying too great a
load. So, again, when my headlights are dimmed these extra lights are
disconnected.

Michael

 

Hi,
Really so. I lived in Phoenix and now here in Calgary Alberta.
Seen more battery trouble down there than up here. One failing cell
in a battery can show that kind of problem too.