Oscillating Interior/external Lights

[RCNV]

I am having this issue with our RX300

when the car is started and without turning on the headlights or the radio (only the auxilliary lights: side marker, licence plates, tailight) or when we turn on the interior dome light. we can perceive that there is some flickering/oscillating. The illumination is not stable, something like if the current was changing.

if it turn on the headlights, i can perceive them oscillating when i contrast the lights in a dark area. if i turn on the heater and the radio, it seems not to make it worst or go away.

Any ideas, I am vaguely speculating that it could be either the alternator about going bad or something with a voltage regulator?

So far we had no troubles starting, we drive the rx on the weekends so pretty much we used it 2 to 4 times a month. it currently has 71000 mi

thank you

RCNV

[SKperformance]

Have you tried hitting the bulb?

It might be almost dead.

[wwest]

Remove both battery terminals, clean and burnish the battery posts and the inside of the cable connections, reinstall and tighten firmly and carefully. Check that the other end of the cables are firmly and tightly attached.

[RCNV]

Remove both battery terminals, clean and burnish the battery posts and the inside of the cable connections, reinstall and tighten firmly and carefully. Check that the other end of the cables are firmly and tightly attached.

I will try the battery post cleaning workaround,

the problem is not limited to one bulb, its on the corner lights, healights, dash indicator lights, door lights, tailights.

I seen old cars and some trailer trucks with the same issue before when driving around. Some because their cars are too old or others because they are obiously using a lot of power due to their loud bumping music..thus all their ilumination oscillates when their music is on.

Thanks

RCNV

[RCNV]

I tried the cleaning the battery contacts, but no money.

The problem is still there, and it gets kind of anoying when it is very dark, specially on the dome light..

Any more ideas?

thanks

RCNV

[Jon in Raleigh, NC]

Check your fuses. They're all obviously intact to some degree, but one or more could be weakening. Remove, clean, and re-install your fuses and their connectors, ensuring that you keep the correct amperage in each fuse port. Your owners manual will have a schematic diagram of your fusebox. Find it, study it, and try to determine if the systems that are wavering are all wired through the same fuse or couple of fuses.

This may not be the problem, but fuses are always the first component you should check with any electrical problem in any vehicle. It's easy, fast, and best of all free to check your fuses first.

[bartkat]

Have you checked your alternator belt?

I don't know if that car has a battery charge meter or not, but if it does, it should read about 13 volts. Also watch that meter with the engine idling and turn on the lights. It should still hold the 13 v.

[wwest]

Dead, or almost dead, battery cell?

The way the alternator works is via pulse modulation. The regulator calls for full alternator output and if the battery is fully charged already the output quickly reaches the upper voltage limit and the regulator opens the ciruit. This all happens about 100 times a second to no flickering is visible, generally. If the battery is not well charged it takes longer for the voltage to rise and the pulse duration is longer.

The flickering you see may have two distinct causes. An open, or high resistance battery connection will allow the alternator output to "spike", which you will see as flickering. A battery that cannot be fully charged, a dead cell, can do the same thing.

There should be a rather large guage wire directly from the battery positive post to the regulator (sometimes within the alternator), check that it has good connections on both ends also. And check that the alternator/regulator grounding posts are well connected.

Swap in a different 12v car battery temporarily??

[sidewinder]

I would have the alternator checked- specifically the regulator as this is quite often a problem associated with regulators. On some older model card the regulator is seperate fom the alternator but Lexus has integrated regulators so you will probably have to replace/exchange the alternator if the regulator is bad. Hope this helps.

[KeithD]

I'm having the same problem here. What did you find out?

[tmo]

I'm having the same problem too. 2000 rx300. Took it back to dealer twice and they can't figure it out. They told it was "normal". Unsatisfied, I called Lexus customer service to report the problem. They called back but they said they never heard of this problem and they'd get back to me. That was 2 months ago. I give up.

[bowtie3]

My wife has a 2000 RX 300 [ 50,000 miles ]. I noticed after she bought it 2 years ago that the interior lights " pulsated " when I would start it up in the garage. When I brought it to the attention of the dealer service department I was told that the technician " could not duplicate problem " [ still covered under Certified Warranty ]. It's easily noticable, especially in the evening. Since then I've just accepted it as one of the " quirks " of RX 300 ownership. I've been a GM technician for many years and I can remember when this very problem could be traced to a battery connection or a starter/alternator ground.

[SKperformance]

Depnding on how good the battery is it could be the battery or just the normal cycle of the alternator charging it after a cold start

[tmo]

I removed the negative cable with the engine running and the problem got WAY worse, headlights and all other lights pulsated wildly, worse as the engine revved. I pulled the vehicle out of the garage and tried to drive it and it just stalled. I think this may be a bad alternator/ voltage regulator problem. If it is, I will expect that Lexus reimburse me for the cost of the alternator.

[lenore]

I removed the negative cable with the engine running and the problem got WAY worse, headlights and all other lights pulsated wildly, worse as the engine revved.  I pulled the vehicle out of the garage and tried to drive it and it just stalled.  I think this may be a bad alternator/ voltage regulator problem.  If it is, I will expect that Lexus reimburse me for the cost of the alternator.

←

Whoa, dont do that, you could wife the regulator on the alternator. Check your plug connection on the alternator itself. It may have corrosion. Also their is probably a fuseable link in the 12v from the battery, but I do not know where. Voltage while the engine is running should be 12.5 to 14 volts across the battery terminal. Good luck. The other thing is a bad ground connection from the engine block to chassis.

[mikey00]

There are many possible causes of a problem like this as mentioned above. However, the Panasonic battery in the RX does not have a very good track record and is most likely the cause. I suggest you do a search on "battery" here and on other RX forums you will find many similiar problems caused by the battery. Either temporarily swap out the battery for a test as suggested above or just pick up a replacement battery. Only cost about $40 at Costco and Kirkland is made by Johnston Controls, one of the best manufacturers and also maker of the Optima. If you have the original Panasonic battery in a 00 RX, you will need to be replacing it soon anyway.

[tmo]

Dealer already replaced the battery and checked the connections. I have a couple of friends with rx300's and their lights are rock solid, have to live with the flickering for now, I guess.