The dome light in our 2000 RX keeps burning out. After I install a new light bulb it lasts for maybe a month and then it blows. I've gone through about 5 now. Anyone have any ideas on how to get the dome light to stop blowing? thanks!

 

Just a wild guess, but are you still on the original battery? No personal experience, but I keep reading here that a dying battery can have unexpected symptoms.

 

Thanks for the reply - I wish that was it - I got a new battery about 6 months ago. So, that's not it. Anyone else have an idea? Let me kow. Thanks!

 

Do you have a DC voltmeter? Measure the voltage at the lamp socket (with the bulb removed).

Also, what type bulb are you using? Are you sure it's the specified type?

 

I assume you are using the right oem bulb [that would eliminate lot of variables].

Here is what happens in a bulb ... fillament provides resitance to electron flow and when the voltage potential [12v] forces the flow of electrons the fillament heats up and glows. The little hidden fact is that the cold {off} resistance of the fillament is much lower than the hot {on-glowing}. Knowing this you can realize that the bulb gets hammered when you turn it on. [Have you noticed that bulbs as a rule never pop when they are glowing ... it happens when you turn them on]

Bulbs are expected to handle some of the hammering .... BUT .. if you have a faulty switch which arcs then the current surge (hammer affect) goes on for a while leading to an early demise of the bulb. I just mentioned the switch but for a circuit there are other possible causes.

1. Bad connections ... terminals of the bulb and scoket .. clean and secure by increasing tension.
2. Faulty switch (you will have to figure out which door switch or button is the culprit)
3. Connectors: In a vehicle wires interconnect through connectors and one of them could be faulty.
4. Bad wire (very unlikely in Lexus)

Items 2 and 3 are can be really difficult to pin down. It is inconcvinient but I can vouch that even a well intentioned dealer/mechanic can have a fit trying to figure out the source of the fault. At times it may be worth keep changing the darn bulb then to rip the vehicle apart and keep replacing things to isolate an elusive problem.

Bottom line: Try securing the bulb contact. and if it does not solve the problem .. just keep replacing bulbs. An EE might suggest experimenting with a capacitor across the bulb to buffer the hammer effect.

Salim

 

I'm a EE and I might suggest that . Maybe 1-10 microfarads, if there's room for it.

 

When you install the new bulb, try not to touch the bulb with your fingers or anything. I've been told that installing headlamp bulbs not to touch the bulb because it decreases lifespan, i'm not sure if it applies but it's worth a shot? good luck.

 

Resurrecting this old thread..... I did a search and could not find anything too helpful. So has anyone found the fix to this elusive problem? Currently I am burning out the dome light bulb ever 2 weeks, so I would like to fix the problem once and for all.

 

I am burning out dome lights every month, haven't figured it out. seems to be in securely, although I have broken a few extracting them. I did have to replace the battery last month, maybe that was the problem. I am going to try a new bulb AGAIN.

 

Have you made sure the bulb contacts are securely connected?
Do you see any tell tale signs of soot/arcing on one or both ends of the bulb?
Have you narrowed it down to a particular door? (switch)

Salim