Headlights “blink”

[Jpilot]

So, curious if anyone has the same issue or a solution. When I am driving with lights on at night I get a “blink” or reduction in light intensity when I apply the brakes. It seems as though the truck does not have quite enough power to give to both the brake lights and headlights at the same time.
I have done the H9 bulb swap, so there is a little more draw from the headlights, but should be negligible right?

 

[ScottR]

I had this happen when my battery was really low/ on its last leg. After replacement it seems to have gone away. Check your battery health?

 

[fkheath]

I had this happen when my battery was really low/ on its last leg. After replacement it seems to have gone away. Check your battery health?

Also check the alternator voltage. Should be about 14 volts with the engine running and over 12 volts when the engine is off.

 

[Jpilot]

Thanks guys, I will check both. Truck seems to crank and start with no issues, but the battery is the original Panasonic from 2015.

 

[Glandnut]

Also check the alternator voltage. Should be about 14 volts with the engine running and over 12 volts when the engine is off.

Explain to me how you check the voltage output of an alternator with the engine off?

 

[cb1111]

Explain to me how you check the voltage output of an alternator with the engine off?

I was going to say that, but then I figured it would be too snarky.

The OP needs to return his car to stock to see if his problem goes away.

 

[Jpilot]

I was going to say that, but then I figured it would be too snarky.

The OP needs to return his car to stock to see if his problem goes away.

LOL, funny stuff. I know what he was trying to say, alternator with car on, battery with car off. :rofl:

 

[Glandnut]

Nah, not trying to be snarky at all. I was just being direct and making sure there wasn't something I was missing.

 

[lunchboxtheman]

I have this exact issue too. I have also done the h9 swap but have a pretty new odyssey group 34r with a voltage booster. So my alternator voltage is plenty high. Voltage doesn’t seem to be the issue.

I don’t remember having this issue with stock configuration but I can’t say for sure it wasn’t an issue. I just may not have noticed.

 

[Slubgub]

Same here, thought I was just seeing things with nose dive when braking and shadows playing tricks on me. Also have done the h9 swap, but all other electrical is stock. Original battery, almost three years old now.

 

[Jpilot]

So, I am going to temporarily put the H11 bulbs back in and see if the problem persists. Easy way to check to see if the H9 is the culprit.
Will check back later.