Hi folks, I took this pic last night while returning from an overnight trip to Ann Arbor (1300 miles total). The LKA, DRCC, and Auto high beam are all turned on. The blue dash light fluctuates in brightness at certain times. I have noticed this for several months. The light really does not flicker, so I don't think it is some kind of loose contact. Sometimes, but not every time, when I step on the gas, the light gets brighter. Sometimes, coasting or braking makes it go weak or completely dark. At steady speed, it never fluctuates in brightness. This happens whether it is day or night, i.e., the headlights don't have to be on. Has anyone else noticed this? Is this standard operation?

 

Is it just the blue light fluctuates at times?. What about the rest in the instrument panel?. Do they illuminate steady when blue fluctuates?.

 

All other illumination stays steady, only the blue light fluctuates.

 

I'll take a guess and say, something seems to be causing the alternator voltage to vary more than normal, perhaps it is overloaded. The alternator puts out more power as the engine RPMs increase. Have you replaced your flooded cell battery with an AGM battery? it might be a good idea to have your battery tested.

 

I agree with jmcraney. I had similar symptoms in my GX just yesterday, turned out to be battery issue. In my case all lights were flickering.

These modern cars are very sensitive to current draw. If I were you, would load test both alternator and battery. Constant low or high current flow will cause issues in long run.

Added : since you mentioned this happens while driving only, it could be the alternator.

 

Thanks, guys, I will get it checked out. The dealer installed a new AC Delco battery last year and 10K miles ago. I think the battery also checked out fine on a December visit, and I have seen this fluctuation prior to that. It happens once in a while, so I don't know if I can reproduce in the shop. I haven't tried to replicate the issue when parked. I should try that and record a short clip.

 

The fact that your battery was replaced so soon gets my attention, especially since you have this other problem with the dash lights. If your battery is prevented from becoming deeply discharged it should last beyond 40 months - batteries do fail prematurely but that is rare. Do you have any information as to why the battery was replaced? I still suspect the battery, or battery connections. If you are unable to get this resolved at a Lexus dealer, you should consider a battery dealer. Battery dealers are usually more knowledgeable and better equipped to sort out these types of problems.

 

Sorry for any confusion about the battery. The original battery was replaced in February 2016 by Lexus of Edison when they performed a PPI before I bought the car (44K miles). They installed an Interstate Cold battery under warranty. In late December 2016 (53K miles), the battery passed a load performance test at my St. Louis Lexus dealer. The car does not have any starting or electrical issues other than this odd dash light behavior, which was noted even before the last load test.

 

Thanks for the clarification. The "AC Delco" got my attention too. I still have concerns about the battery. If you run out of options, take it to an Interstate Battery dealer and tell them about what you are experiencing. They may tell you I am giving you bad advice.

 

Does it slowly fade in and out? As you are accelerating and decelerating?

 

The blue light all about "efficiency" if it's fading in and out. The last time I test drove an LS with the blue lights they faded in and out depending on how efficient your driving was. When you accelerate the blue light gets dim and turns off while when you're coasting or generally not "accelerating" and getting an efficient MPG it fades to a strong blue. Perfectly normal operation as far as I'm aware.

 

Yes it fades in and out slowly during acceleration and coasting or braking.

Yes, this sounds entirely reasonable, and my thinking also. But it does not happen every time. And, if I recall correctly, the light behaved opposite to your description: brighter when accelerating, and dimmer or off when slowing down. But I am not 100% sure about this. I will have make more careful observations. I haven't yet bothered to check the owner's manual, but maybe there is some description of this feature in there.

I am hoping more 2013+ members will chime in.

 

Well I guess you'll just have to junk it and get another. I'll take it from you. I don't really want to with all the light issues, but I'll do it to help you....

 

LOL, be careful what you wish for; those blue lights will absolutely drive you bat crazy. I wouldn't wish it on anybody. I will take one for the team and just grin and bear it ...

 

enoch was getting at was I was going to say its an efficiency light essentially.