Go Back   Club Lexus Forums > Lexus Model Forums > LS Models > LS400
Sign in using an external account
Register Forgot Password?

1998 LS400 Rear interior door light not working, low voltage

Reply
 
 
 
 
Thread Tools Search this Thread Display Modes
Old 06-22-14, 06:48 PM   #1
KC98LS
Driver School Candidate
Trader Score: (0)
 
Join Date: Jun 2014
Location: Missouri
Posts: 14
Unhappy 1998 LS400 Rear interior door light not working, low voltage

Hello there, apologies if this has been asked before, I searched around and didn't find anything.


I recently bought a 1998 LS400, when I open the rear doors, the lights on the left side don't turn on, however pressing the button turns the right, and left map light on. The center light never turns on though.

I popped the cover off, and tested the bulb in the other socket, and it worked fine. I also popped the light assembly out, and tested the voltage using my multi-meter. The right side, which works measures 12V, the left side which doesn't measures 2.85V.



Any input on what might be the problem here?

Of interest, all of the other lights appear to work in the car, also all of the interior lights are LEDs, being a 1998 I assume this is stock, but correct me if I'm wrong.


Pic related, the part that's hanging down is putting out 2.85 volts, whereas the right side is putting out the correct 12v.

Click the image to open in full size.
This ad is not displayed to registered members.
Register your free account today and become a member on Club Lexus!
KC98LS is offline   Reply With Quote
Old 06-23-14, 07:01 AM   #2
sha4000
Lexus Champion
Trader Score: (1)
 
sha4000's Avatar
 
Join Date: Aug 2005
Location: N.Y.
Posts: 3,491
Default

No those LEDs are not stock. The previous owner put them in there so maybe they messed something up.
__________________
1998 LS 400
sha4000 is offline   Reply With Quote
Old 06-23-14, 05:38 PM   #3
KC98LS
Driver School Candidate
Trader Score: (0)
 
Join Date: Jun 2014
Location: Missouri
Posts: 14
Default

Quote:
Originally Posted by sha4000 View Post
No those LEDs are not stock. The previous owner put them in there so maybe they messed something up.
Good to know, any ideas what they may have messed up?

I heard there's an integration box that controls interior lighting, would that somehow partially fail?
KC98LS is offline   Reply With Quote
Old 06-23-14, 07:30 PM   #4
Yamae
Lexus Test Driver
Trader Score: (0)
 
Join Date: Aug 2011
Location: Japan
Posts: 852
Default

There are semiconductors in that box and those fail when a short circuit is caused because of too much current but less current to open the fuse. You probably need to replace the box to fix the problem. I knew a young guy who failed trying to install a led light bulb and accidentally he made a short circuit. He ended up to replace the box at the dealership.

Dealerships only replace the unit and owners need to pay some big money. But this is very common among modern cars. I often fix those different units as a volunteer and I know how easy to fix those units just finding the failed component and replace it. This needs some skills, but people need to know electronics affairs some more.
Yamae is offline   Reply With Quote
Old 06-24-14, 11:00 AM   #5
KC98LS
Driver School Candidate
Trader Score: (0)
 
Join Date: Jun 2014
Location: Missouri
Posts: 14
Default

Quote:
Originally Posted by Yamae View Post
There are semiconductors in that box and those fail when a short circuit is caused because of too much current but less current to open the fuse. You probably need to replace the box to fix the problem. I knew a young guy who failed trying to install a led light bulb and accidentally he made a short circuit. He ended up to replace the box at the dealership.

Dealerships only replace the unit and owners need to pay some big money. But this is very common among modern cars. I often fix those different units as a volunteer and I know how easy to fix those units just finding the failed component and replace it. This needs some skills, but people need to know electronics affairs some more.
Good to know, what exactly do you mean by the box?
KC98LS is offline   Reply With Quote
Old 06-24-14, 02:12 PM   #6
timmy0tool
Lexus Champion
Trader Score: (5)
 
timmy0tool's Avatar
 
Join Date: Sep 2008
Location: 909/626/714, SoCal
Posts: 2,438
Send a message via AIM to timmy0tool
Default

sounds like you simply have a burnt out LED. most LEDs are made of poor quality and don't last as long as they claim to. change to a regular bulb and see if you still have the problem.

next i would check your door pin triggers. they ground when the door is opened to trigger the light to turn on. they are located in the door jams and is usually covered in rubber. if the rubber is torn, there is a good chance gunk has built up inside and is intermittent.
__________________
lateral Gangsta
timmy0tool is online now   Reply With Quote
Old 06-24-14, 02:26 PM   #7
KC98LS
Driver School Candidate
Trader Score: (0)
 
Join Date: Jun 2014
Location: Missouri
Posts: 14
Default

Quote:
Originally Posted by timmy0tool View Post
sounds like you simply have a burnt out LED. most LEDs are made of poor quality and don't last as long as they claim to. change to a regular bulb and see if you still have the problem.

next i would check your door pin triggers. they ground when the door is opened to trigger the light to turn on. they are located in the door jams and is usually covered in rubber. if the rubber is torn, there is a good chance gunk has built up inside and is intermittent.
I actually tested the bulb, and it is good.

I'll try the door pin, any tips on how to do that?

Thanks.
KC98LS is offline   Reply With Quote
Old 06-24-14, 05:16 PM   #8
Yamae
Lexus Test Driver
Trader Score: (0)
 
Join Date: Aug 2011
Location: Japan
Posts: 852
Default

Quote:
Originally Posted by KC98LS View Post
I actually tested the bulb, and it is good.

I'll try the door pin, any tips on how to do that?

Thanks.
You need to replace the integration box which controls interior lightings. The output voltage 2.85V from the box simply means that the box is not working properly. The semiconductor inside must be damaged. Toyota does not supply those semiconductors as parts and usually there is almost no way to fix the box. Only those who analyze the circuit and replace damaged parts can do some. I seldom find those people though.
Yamae is offline   Reply With Quote
Old 06-24-14, 05:32 PM   #9
KC98LS
Driver School Candidate
Trader Score: (0)
 
Join Date: Jun 2014
Location: Missouri
Posts: 14
Default

Quote:
Originally Posted by Yamae View Post
You need to replace the integration box which controls interior lightings. The output voltage 2.85V from the box simply means that the box is not working properly. The semiconductor inside must be damaged. Toyota does not supply those semiconductors as parts and usually there is almost no way to fix the box. Only those who analyze the circuit and replace damaged parts can do some. I seldom find those people though.

Where exactly is the integration box located in the car?


Also, update: The left rear door switch or whatever you want to call it definitely works, as opening the left rear door, turns on the bottom door light, and the dash door open message.
KC98LS is offline   Reply With Quote
Old 06-24-14, 05:59 PM   #10
Yamae
Lexus Test Driver
Trader Score: (0)
 
Join Date: Aug 2011
Location: Japan
Posts: 852
Default

Quote:
Originally Posted by KC98LS View Post
Where exactly is the integration box located in the car?


Also, update: The left rear door switch or whatever you want to call it definitely works, as opening the left rear door, turns on the bottom door light, and the dash door open message.
A JDM has it under the dash near the fuse box. I don't know about the USM.
Don't pay any attention for the switch. Simply tackle the box. The most inexpensive way may be to go to a junk yard and buy the box and replace it.
Yamae is offline   Reply With Quote
Old 07-10-14, 10:11 PM   #11
KC98LS
Driver School Candidate
Trader Score: (0)
 
Join Date: Jun 2014
Location: Missouri
Posts: 14
Default

Does anyone have any ideas on where the integration box is in the US model? Been a bit busy, and haven't looked for it.

Update: Is this what I'm looking for?

Click the image to open in full size.

Last edited by KC98LS; 07-18-14 at 05:44 PM.. Reason: Picture added.
KC98LS is offline   Reply With Quote
Old 08-31-14, 07:13 PM   #12
KC98LS
Driver School Candidate
Trader Score: (0)
 
Join Date: Jun 2014
Location: Missouri
Posts: 14
Default

Bump!

Any input would be greatly appreciated. I really want to fix this issue, and get it off of my list.
KC98LS is offline   Reply With Quote
Old 08-31-14, 07:13 PM
 
 
 
 
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Help me diagnose Battery/Alternator problem (with voltage readings)? btanchors GS - Second Generation 13 08-06-14 09:20 PM
Left tail light completely out after cleaning sockets LexusLove1 Performance & Maintenance 1 08-22-13 05:49 PM
Fast Install of Illuminated Scuff Plates rljones IS - Second Generation 187 06-25-13 01:05 PM
98 LS400 Will Turnover, Won't Start no CEL fuz16 LS400 14 03-26-13 09:45 PM
Left outer brake light not working! WDoherty Performance & Maintenance 5 11-06-12 08:42 PM

All times are GMT -7. The time now is 11:24 AM.

Join ClubLexus
Advertising


Copyright © 2000-2008 Internet Brands, Inc. All Rights Reserved
Privacy Policy | Disclaimer | Terms of Use | JOBS


Get all contact info