Interior Radio Etc Lights "flickering"

[LexKid630]

I have installed LED's in the place, and in addition to the bulbs in the center console etc. of our 03 rx300. Where one bulb would be, i have wired 3 LED' with appropriate resistor values etc.

I began to notice that every one of the LED sets i put in started to flicker. A very slight flicker, but still enough to get annoying. I first assumed i had the incorrect resistor values or something, so i pulled everything out and tested them with 12V from an outlet adapter. They're fine! The LED's aren't burned out, in fact i have greater than minimum resistor values.

I then thought the issue could have been that the in voltage wasn't exactly 12 (since the alternator can fluctuate) so i added 12V voltage regulators to each LED set. The flickering didn't change.

I also noticed that the LED's i've added in the car not only on the interior lights (like for the radio etc) but the LED's i've wired on the cigarette lighter circuit also have the flickering.

I initially thought the issue was with the LED's only for the fact that the bulbs on the same circuit didn't flicker- i now realize it could be because bulbs aren't as "quick" in illumination as LED's are, so if there was for some reason a fluctiation in IN voltage, the bulbs wouldn't show it up as much as LED's would.

What could the problem be? Why would the car be giving fluctuating voltage? There is obv. not a constant voltage going to the circuit, for some reason the car's voltage is dropping then raising so slightly that only the LED's can pick it up.

I know my battery has been dieing too easiely lately... could a new battery help?

ALSO: The problem only occurs when the car is running. When the car is in ACC (engine off) the flickering goes away, but it seems the LED's aren't as bright.

Thanks for any help/input!

[smooth1]

From your description, I would consider the alternator your issue. It contains the regulator also. Try swapping to a new alternator which should fix the battery dying issue also.

[lenore]

You should check the Alternator output, should be 13.5 to 14.5 when the engine is running. If it isnt than the alternator could be failing, possibly the bridge rectifier, which could cause the flickering. I would clean the terminals on the battery as a first step and also check for a good ground connection to the engine block.

[Grumpa72]

It is my understanding the LED require a constant voltage and I would guess that the minor fluctuations that normally occur in an alternator may be the culprit. I know that the various decorative household LED lights cannot have a resistor on them that allows you to dim the lighting. Have you tried going back to the tried-and-true factory setup?

[LexKid630]

Thanks for the suggestions, i will try the battery terminals and everything i know how to do myself :(

How do i check the voltage from the alternator? I checked the voltage straight from the battery, but i don't even know where the alternator is :(

I put all the bulbs back, and couldn't notice any flicker. I'm just guessing that the bulbs just don't show the slight fluctuation- but i bet it's there since the LED's are working with an outside 12V source. The issue is definitely in the voltage coming from the car.

[mikey00]

Thanks for the suggestions, i will try the battery terminals and everything i know how to do myself :(

How do i check the voltage from the alternator? I checked the voltage straight from the battery, but i don't even know where the alternator is :(

I put all the bulbs back, and couldn't notice any flicker. I'm just guessing that the bulbs just don't show the slight fluctuation- but i bet it's there since the LED's are working with an outside 12V source. The issue is definitely in the voltage coming from the car.

Why not just wire a test setup with your LED's ( or even just one) connected to a cigarette lighter plug. Try it in some friends cars , another RX would be best. If the problem still exists, there is no need to go troubleshooting your RX for a problem that doesn't exist. I suspect they are going to flicker wherever you put them. LED flickering in automotive use is a common problem. Some have solved the problem by leaving the bulb connected in parallel with the LED. This is the same concept as using the resistors.

[lenore]

Thanks for the suggestions, i will try the battery terminals and everything i know how to do myself :(

How do i check the voltage from the alternator? I checked the voltage straight from the battery, but i don't even know where the alternator is :(

I put all the bulbs back, and couldn't notice any flicker. I'm just guessing that the bulbs just don't show the slight fluctuation- but i bet it's there since the LED's are working with an outside 12V source. The issue is definitely in the voltage coming from the car.

Just for your info, you check the alternator voltage at the battery terminals. The Battery normally will measure about 12.5 volts with engine off, with engine on the voltage will go up to 13.5 to 14.5 showing that the alternator is charging. Good luck...

[LexKid630]

I took the car to sears this afternoon and had them replace the battery (since i needed one anyway). I also had them check the alternator.

The tech said the battery that was in there was "on its way out" but that the alternator tested perfectly. I had originally told them to put some "platinum" battery in, but they said it wouldn't fit. So i opted for the second best option, something gold? They said because of the "inconvenience" they'd do a full fuel savings cleaning- something to clean the oil, gas, etc.). $79 cleaning free? I picked a good place to go!

Anyways, the problem still persists. Car starts up perfectly though, i can tell it's a new battery.

The guy gave me a slip, it reads:

Alternator belt and or the belt tensioner are ok

Battery Results:

SPEC. CCA= 640

GOOD BATTERY

STARTER TEST: CRANKING VOLTS: 11.04 GOOD

CHARGING TEST:

LOAD VOLTS: 13.82

NO_LOAD VOLTS: 14.00

DIODES GOOD

COMMENTS: All systems good

Someone suggested that it may just be the car's nature. They also said i should put a capacitor on the + and - inputs of 12V voltage regulators to each set of LED's to get rid of the "noise".

I have a family member with a 2001 RX300, next time i see her i will test hers. I'll make an LED plug set-up to test it.

The only thing that still baffles me is why this only happens when the car's engine is on. When it's in ACC the probem goes away. I STILL think the alternator is the cause based on what you guys said, but the tech assured me it was fine. My guess is the equipment he had just couldn't pick up the irregularity either?

[Grumpa72]

First, it is in the interest of the store to sell you their "best" battery and of course they call it platinum or some other excuisite material. Imagine them asking you if you the wood, tin, or lead series battery. ;) Regardless, you have the battery so move on. I mentioned in my previous post that LEDs are very susceptible to voltage flucuations. I am betting that even a .5 volt variance can be seen in an LED. The reason that you see the difference only when the engine is running is that there are variances in the alternator whereas the battery puts out a constant voltage.

[LexKid630]

Do you think that these variances in the alternator are normal for the RX300? I thought the regulator in the alternator was supposed to keep a constant output voltage...

[LexKid630]

I also notice the slight flicker whenever the compressor goes on/off for the A/C. It also flickers whenever i turn anything electrical on or off, like headlights, high beams especially.

This really doesn't seem normal! The new battery has been in the car for a few weeks and no improvement. Anyone else have any other ideas?

[mikey00]

I also notice the slight flicker whenever the compressor goes on/off for the A/C. It also flickers whenever i turn anything electrical on or off, like headlights, high beams especially.

This really doesn't seem normal! The new battery has been in the car for a few weeks and no improvement. Anyone else have any other ideas?

Whatever happened to testing your LED setup on your friend's RX? I really think you are trying to fix something that is not broke.