Taillight Failure 2003 Ls430

[Sardar]

Brothers and partners in crime,

Just bought a 2003 LS430. I really enjoy driving the car; its my first Lexus. Must say, the engine and car is ultra quiet when compared to my old infiniti Q45. However, the LS has a problem that is annoying the s$*t out of me. At night, as soon as I start the engine, the taillamp failure light comes on the dash with the red exclamation mark. I don't need to step on the brake for this to happen, so its one of the taillights that's causing the failure light.

I changed EVERY bulb in the back, inclduing the turn signals making sure that it is the right wattage for the job. All bulbs are high quality from Autozone. Every single light is lite up in the back, I verified this maybe 50 times already. The sign still comes on. I measured the voltage at the taillights, all are reading at 12.15 volts.

Interesting point - the light does NOT come on if I turn the key to the start position, only when I crank and start the engine, does the warning come on.

I can't figure this out. Someone else must have had this problem - how do I fix this? Any help would be much appreciated.

C

[VBdenny]

The light should come on when you crank since that it how you determine that the bulb is functioning. As long as it goes off, everything is fine.

[jainla]

Have you checked the center high mounted stoplight? That drove me NUTS for weeks until i figured it out. Also make sure all the bulbs are seated properly; I had one actually pop out. The should click into place. Also check fuses maybe?

Brothers and partners in crime,

Just bought a 2003 LS430. I really enjoy driving the car; its my first Lexus. Must say, the engine and car is ultra quiet when compared to my old infiniti Q45. However, the LS has a problem that is annoying the s$*t out of me. At night, as soon as I start the engine, the taillamp failure light comes on the dash with the red exclamation mark. I don't need to step on the brake for this to happen, so its one of the taillights that's causing the failure light.

I changed EVERY bulb in the back, inclduing the turn signals making sure that it is the right wattage for the job. All bulbs are high quality from Autozone. Every single light is lite up in the back, I verified this maybe 50 times already. The sign still comes on. I measured the voltage at the taillights, all are reading at 12.15 volts.

Interesting point - the light does NOT come on if I turn the key to the start position, only when I crank and start the engine, does the warning come on.

I can't figure this out. Someone else must have had this problem - how do I fix this? Any help would be much appreciated.

C

[Sardar]

Have you checked the center high mounted stoplight? That drove me NUTS for weeks until i figured it out. Also make sure all the bulbs are seated properly; I had one actually pop out. The should click into place. Also check fuses maybe?

Thanks for the relies. As for the first comment, the light stays on after starting the car, it does not go away until I turn off the lights, manually.

For the second comment - I thought the stoplight mounted in the back only comes on when I step on the brake? The failure light comes on as soon as I turn the lights on, WITHOUT steping on the brake. So I am assuming that this is related to only the taillights and not the brake lights. Am I correct in assuming this?

CJ

[VBdenny]

the bulb out indicator comes on even if one of the brake lights is out. Interesting that the light should illuminate when the key is in the start position.

[1990LS400]

If all the bulbs are good and firmly in place and if you don't seen any issues with the bulb sockets or the wires leading to the sockets, i wouldn't hurt to remove the trim in the trunk and look for a loose, frayed or damaged wire. Maybe the car has been in an accident and a ground wire was broken or not screwed back into place.

As I reported several times in the past, the tail light failure warning in my previous LS400 was on for several years before I found that a "scotch lock" connector for my trailer light harness in the trunk had come loose from one of the tail light wires. I had spent countless hours looking for the cause of the problem and had paid my mechanic to take a look too. I felt a little silly when I snapped the connector firmly together and the warning light went out. Funny, someone on this or another forum reported the same issue and his problem also turned out to be a loose trailer light harness connector.

Your problem may well be something simple. A bulb with a loose filament that you missed changing, a corroded socket contact, a wire mashed/damaged by the previous owner carrying something in the trunk, etc.

[VBdenny]

I had one of my tailights that the contacts inside the socket were not set correctly so I cleaned it all up and the light (indicator) went out.

[KAN64]

Trying to replace the upper right tail light on my '03 LS430.  But after turning the bulb assembly 1/4 turn counterclockwise, it will come out.  I can easily remove the lower tail light assembly but upper one will not come out.  What's holding it in?

[Bernard Williams]

My tail light failure warning light is on my 2003 Ls430 all Blubs and Fuses are good l need know how to repair this problem anyone know ? 

[paulo57509]

Check the lights in the front.  I wouldn't have guessed that the fronts are connected to the same failure sensing circuit.

https://www.clublexus.com/forums/ls-3rd-gen-2001-2006/905427-has-anyone-by-passed-the-lamp-failure-in-an-04-ls-430-a.html#post10392051