OK, I'll bite. I've got an intermittent problem that has baffled my local Lexus dealer. It is a VERY frustrating condition that you would not expect from a Lexus.

Very rarely, the automatic headlight shutoff on my RX300 doesn't shut the lights off. After I'd had the car a few months, I came to leave the switch in Auto position, and trust the lights to go off after the 30 second or so interval. So, when this started happening (about 14 months ago) I would come out to my car and find a dead battery.

Now, I usually hit the Lock button twice to make sure the lights are out. That defeats the convenience, obviously.

The local Lexus dealer has had it twice. The first time they replaced the light switch on the driver door, saying there was a slight current draw at all times.

The second time they kept the car a week, found nothing, and replaced the battery under warranty. All those times the battery went dead added up.

Other observations:

-- When this happens, if I open and close the driver door OR the passenger door, and try again, the light always goes out as it should.

-- Also very rarely, sometimes the car will not react to the remote when I approach the car. If I use the key to open the door and close it again, the remote works again.

-- I thought maybe this was associated with temperature, as it happens more in cold weather, but it has happened in the summer.

I conclude that there is a digital computer controlling all of this, and it has a very intermittent problem where it freezes up. I think Lexus should replace the computer.

As to the dealership: They have been very polite but not as helpful as hoped:

-- The repair people came up with a theory that if I open the driver door while the car is running and the headlights are on, then turn off the car and get out, then close the door, and hit the lock button, the lights are supposed to stay on. That's not what the owner's manual says, and I tested this on a brand new RX300, and it isn't true.

-- They loaned me a fairly beat-up Camry when they kept the car for a week. (I bought the car used from someone who bought it from that dealer; they say I don't get a Lexus loaner even though under warranty. I was also told that Roadside Assistance only applies to the original owner)

I am sure this condition will happen again. What action would you take the moment it does?

I will tell you it is embarrassing to have to bribe a construction worker $20 to jump start your Lexus. One day, I missed an appointment to refinance my house when this bit me at the wrong time. I think the loan officer was skeptical that a Lexus might behave this way.

 

first of all you never stated what year it was? that would help.second the moment it does happen have it towed to the dealer.third lexus dealers dont have to give a lexus loaner its a perk so be thankful you get something.let the dealer figure it out i am sure they will.why not try the maintenance section



have a nice day

 

It's a 1999.

It usually isn't convenient to have it towed. Plus, what good is that going to do? As I stated clearly, when you open the door, the problem goes away.

I guess it would do good in the sense that they'd believe there is a problem.

 

This most probably is an independant event. RX like other Lexus shuts out the remote sensor if it detects similar but not the exact code. If you lock your RX and some in the vicinity unlocks their RX, your's will shut off its remote. This true feature protects your RX against scanner-broadcaster tech theft.

Salim

 

Very interesting, Salim. Hmmm. It's happened in my driveway, and I leave on a quiet cul-de-sac. There are Lexi in the neighborhood but none in the immediate vicinity.

I thought modern car remotes used rollover codes with billions of combinations and were much harder to ****** using scanners?

Do you happen to know if the same computer controls the headlight shutoff and the remote control?

 

I do not have the electrical diagram and also do NOT have the know how of the security system on RX. Sorry I can not be of any help here.

Intermitent problems are hard to diagnose. Strange as it may seem, but one has to pray and wait for a permanent failure.

Salim

 

Yes, I know, intermittent problems are incredibly hard to diagnose. But this one is damn inconvenient when it does happen. I am thinking about giving myself one of those self-jump-start gizmos and leaving it in the back of the RX300.

The standard computer repair technique is to swap out parts and see if the problem gets better. Lexus swapped out a door switch and things didn't get better. Now I want them to swap out something else -- whatever digital device is the controller for the headlights.

My guess is that what may be happening is the digital controller isn't receiving the interrupt when the door closes. I believe it is per spec for the light to never time out if the doors are open, on the theory that you are on the side of the road dealing with an emergency. So it never discovers the door is closed. This could be a hardware glitch or a software problem (timing issue where the "event" isn't properly handled in real time).

 

I would use "lock" "lock" command from the remote or not use "auto" position for lights on that stalk.

Again without the ckt diagram it is hard to guess, but door close sensor and its wire can be eliminated by observing door open light in the cluster, cabin light, and key in ignition buzzer.

Salim

 

I had a similiar problem years ago with a Honda Prelude. It ended up being that the headlights wiring had heated up and melted the plastic insulation. It had melted atop a constant-on wire (i think the clock), and that powered up my lights.

It actually started to burn and smell before the dealer figured out what is was. So have them inspect your wiring harness well.

 

richwig, on our '99 we had intermittent problems with the remote. When it first happened we each stood on opposite sides of our $35k car and could not get in without using the key. As soon as we opened it the remotes immediately worked fine!

I never had the lights stay on and drain the battery though....

Salim, I didn't know that hitting lock/lock would shut the lights out, I have hit that on occasion and not noticed the lights going out on the '99 or '03. Will try it more deliberaately, tks!

Sooner, I made a vow to call the 800# for any sort of major failure in the future and get the car checked out so they can see the problem, risk is some sort of damage by the extra handling so need to be careful signing off on the towing/handling.

 

This is really rare problem and Lexus dealer already replace the door actuator( door switch). There's a Body ECU(not sure it's #1 or 2 Body ECU) that control the lock& unlock and send the signal to auto headlight to turn off, just my WAG( wild a$$ guess).