HeresOtis

This morning I started my car and it turned over instantly. It didn't even crank, it just turned immediately. After letting it warm up, I started driving. My interior lights started pulsating and the SRS light will flash (for 5 seconds) every 7 seconds. I then started to monitor my data via OBD port. I was getting voltage spikes up to 16.8V and the voltage went low as 12.8V, all while driving. Then after about 25 minutes of driving, the spikes calmed down and every thing appears normal.

What can be the cause of this?

mk378

Check that the battery terminals and the main ground wire are good. Then consider it could be the fuse 15 problem or a faulty alternator. The voltage regulator is inside the alternator, most people replace it as a unit. Do not keep driving with high voltage, it will burn up the battery and all your light bulbs.

fcm

Ditto the above voltage regulator. replace alt. 94

youstolemybeer

This is NOT a recommended idea but it works
If you are short on money and long on the week and need an alternator. when you drive the car, make sure every electrical component (lights,heater,fans stereo is on) this will bring down the voltage to just barely above normal. Once you get the money replace the alt and check the battery for water
NOT recommended but if push comes to shove it can be done

HeresOtis

So far, this incident hasn't happened again. I am looking into replacing my alternator.
Though, this still happens every day, as mentioned in my other thread (https://honda-tech.com/forums/honda-...ights-3287935/):
"To add on, whether the lights are pulsating or not, more frequently I've noticed that my interior lights get brighter after I drive over 2500rpm and when I have to come to a stop, they get dim (or normal brightness level?)"

chrysler kid

The dome light is a finicky piece and can do that normally. If your instrument cluster lights are doing this then either your dimmer switch is malfunctioning, or like you are describing you are having a voltage problem

At parts stores are able to test your alternator on the car for free. I highly suggest having it checked now before the problems get more severe

HeresOtis

Update

Recently, I had my car running while I had a multimeter on the positive and negative terminals of the battery. Of course, while the car is running, I'm measuring the voltage that the alternator is pushing out. So while at idle @ about 800 RPM, the voltage kept jumping at values between 14.60 - 15.20 V. It'll reach output 15.15V then jump to 14.62V, for example. Then as I pulled the throttle to rev the engine (I'm assuming about 1500 RPM), the voltage became more stable, but will occasionally jump to a low voltage around 13.60 V. For example, the voltage output is stable at 14.52V then about every 5 seconds or so it will jump to 13.60V then back to 14.52V.
I also pulled disconnected the battery while the car was running and no stutter of the engine, but the same voltage behavior. So the battery is good.

What can cause this weird behavior?

Former User

Did you check fuse 15?

HeresOtis

Yep, the fuse is still intact and fine.

Former User

When you turn the key from off to ON(II), does the charging system warning light in the cluster turn on and stay on?

HeresOtis

Yes, it remains on.

Former User

Why haven't you replaced the alternator?

HeresOtis

I never taken notice of it. That light is never on when the engine is running, like how the CEL comes on. So when it comes on during ON (II), I thought that was normal procedure.

Former User

The light is fine.

The alternator is overcharging the system. Replace it.

HeresOtis

Alright, gotcha.

HeresOtis

Update: I still haven't replaced the alternator because I haven't been focused on and using the car frequently. Another thing I noticed and would like to mention for further documentation and solutions.
When the car gets into the phase of pulsating headlights and interior lights, when I turn on the AC, the lights stop pulsating and return to normal. When I turn off AC, then everything pulsates again. Also, if I have the AC on and step on the gas pedal/throttle (while in park), the lights begin pulsating as well.

To sum it up:
- Car lights pulsate, while in idle
- Lights stop pulsating when AC is turned on, while in idle
- Lights resume pulsating when throttle is applied while AC is on, while in idle

Does this give any of you any further thought for the cause of this? Maybe the belts? Is it still a bad alternator?

civic402lx

HeresOtis

It's in my recent post.

crazyhorse2011

Home boy your alternator is all goofed up. The voltage regulator is what keeps your headlights from getting brighter and brighter til your bulbs blow as you rev your engine up higher in rpm. That behaviour alone is enough to call it quits on that alternator and go get yourself a new one. Cheap reman ones can be had on rock auto if this is just your winter beater. otherwise step it up in wattage a bit and give yourself a more beefy unit.

civic402lx

Y don't you just take everyone's advice and replace the alternator already?
You keep running in circle with this issue. Replace the alternator, confirm issue went away. If not, return the alternator to where you bought it then go back to the chalkboard and diagnose further.

Answer to you issue has been given by more then one member to help you. Y don't you take the time and get to it, instead of wasting time looking for some other answer?
If there are any other possible solution, they would have post it up. They are waiting for you to do you part before they can look for other possibility if the alternator wasn't the issue..