It’s not unknown or unusual for the voltage from the alternator to vary by a small amount between idle and higher rpms. This condition will be magnified at night and in the winter when many other electrical consumers are on. In any event I would expect such a voltage variation to be less than 1 volt and should not be visible to the driver.
If the shop says the alternator is OK, I would go looking at at the headlight circuit for poor or corroded connections.
Can you park the car somewhere dark at night and leaving it idle get out and from in front of the car see if both headlights are the same brightness? Retest with the high beams on. Get a friend to rev the car and see if all the lights gain equally in brightness. If any of the headlights doesn’t react like the others (birghter/dimmer/ doesn’t gain or lose brightness by the same amount) it is NOT an alternator problem, it is an electrical circuit problem in the headlight circuit.
Rats! I was hoping that I was just being unusually persnickety in re: my headlights. They don’t get that much dimmer, just enough for me to notice it out of the corner of my eye.
I can’t cancel this trip, my Aunt will go six kinds of bovine if I don’t get the twins there today, so that we can do “Bfast w/Santa” tomorrow a.m. – however, we’re only going about 70 miles, all via major highways.
I’ll pack some extra blankets just in case.
Thanks for your help, folks - Stranger, that was really nice of you, to google this (I hadn’t found squat, myself). I’ll try that bit with the lights (and radio, perhaps) at my Aunt’s house.
That’s exactly the reason I had for getting rid of mine. It was a 1989 that I bought brand new. I got 53 MP (Imperial) Gallon on the highway. I owned it 14 years and apart from mufflers, tires, and a clutch, i never had to do anything else. Well, oil changes of course. (And the alternator, but that was under warranty.)
I used to fill the car back then for 22 dollars (probably about 13 US bucks at the time) and drive it for 2 weeks! Now I have a Jeep Grand Cherokee and i go through $100 every two weeks.
No problem. You were helpful to me once in an art-related thread and I’ve been hoping for a chance to repay you ever since.
When Googling, do you use the advanced search? I entered “lights” in the ‘all of the words’ field, “Honda” in the ‘exact phrase’ field, and “dim, dimming” in the ‘at least one word’ field. I could have delved into it further by using different search words but I felt I had sufficient hits to determine that the problem most likely wasn’t normal.
I think you’ll be okay for such a trip anyway, fessie. Anytime I’ve had similar problems it was always several days to a few weeks before it got so bad I had to take the time to have it fixed. If you have a cell phone and are travelling in areas where there is coverage, you shouldn’t have a problem that is much more than an inconvenience at worst. Good luck.
When I first started driving, I noticed this, too, and mentioned it to someone. They said it was normal, as well. I’ve had several cars since then, all of them did this to some slight extent, and that alone never was the symptom of a bigger problem. I have had a couple of severe electrical problems along the way, but the symptoms were different and correspondingly much more severe.
I agree with Stranger On A Train. The tech would see a problem if anyone would. And batteries can go without warning. Mine just did this week, but it was over 6 years old.
I agree with this except the technician was looking for a alternator or battery problem. He may never have turned on the headlights depending on how the repair order was written. So assuming it is a headlight problem, he probably never checked for it.
How lovely! I hope your art is thriving!
After I posted my notion about taking extra blankets, I thought “that is really half-assed; a second opinion is what I need”.
So - I called the Honda dealer in Wisconsin that I used to work with, years ago, and described the situation to their Service Tech.
He said there’s a part called an Electrical Load Detector, or ELD, that is related to fuel efficiency and it could possibly be malfunctioning. But more likely it’s just working properly and causing the variation I noticed - he read an internal memo from 2000 that talks about how the ELD works. Honestly, I have a huge headache right at this moment and I can’t recall his exact words — the point of it was the ELD’s signal gives the engine just enough fuel to meet demand, so it’s going to fluctuate the alternator depending on how much I’m accelerating. Or something.
Anyway, thanks for the help!
Our trip was a success, the twins loved Santa! Informed him they would like a T. Rex and a stegosaurus.
Great! Thanks for the update. I’m glad all is well and I hope your kids get all the giant reptiles their hearts desire. 