Stupid light bulb......

pico · 06-30-2005, 04:01 AM

My battery was drained last week, I took out the battery and let autozone recharge it for me. Then i measured the reisistance between the 2 cables and it show 3.7ohm!!!

I checked all the fuse and they're all fine and after 2hrs of peek and poke finally i find out that my trunk light bulb was shorted!! I always thought light bulb will be opened rather than shorted when they goes bad.....

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Mulder · 06-30-2005, 09:04 AM

That is actually a normal resistance reading for a light bulb. The problem isn't the bulb itself, but that it is connected when the trunk is closed. Your problem actually lies with the trunk light switch, rather than the bulb. The switch is either defective or not adjusted properly. You can confirm this by looking through the rear seat pass-through when the trunk is closed, if the light is still on you'll see it. If it is proceed to either adjust or replace the switch.

pico · 06-30-2005, 03:12 PM

thats true......... but isn't 3.7ohm kinda low??? which means it draws >3 amps when its on..... thats about 40W?!

Mulder · 06-30-2005, 04:21 PM

The resistance of the filament increases when it heats up. So did you check your switch?

avk · 06-30-2005, 04:34 PM

The resistance goes up some 10 times, so the power will be in 5W range which is about right.

pico · 06-30-2005, 09:41 PM

ic, I haven't has time to check it yet. but let say if the switch is bad, which means i has it on for a few days, will it drain my battery out? or do u think i have some other stuff thats drawing power as well??? I guess the light buld is smart and i'm the stupid one...

Mulder · 06-30-2005, 09:49 PM

Yes a stuck-on trunk light will drain the battery if left alone for a few days. Exactly how long it will take depends on the battery condition and state of charge(may not be too good if it's been discharged already). If you can't get to it right away, just take the bulb out.
Another sign it's been on is if you open the trunk to pull the bulb, and it feels very hot from being on a long time.

John UK · 07-01-2005, 04:16 AM

It's easy to check if the light is on all the time.
Climb into the trunk and shut the lid.
.
.
.
.
Just make sure a (good) friend is there to let you out again.

John

Mulder · 07-01-2005, 06:14 AM

^
Not necessary with the pass-through.

Rapid_Roo · 07-01-2005, 11:10 AM

Quote:

Originally Posted by Mulder

You can confirm this by looking through the rear seat pass-through when the trunk is closed, if the light is still on you'll see it. If it is proceed to either adjust or replace the switch.

can't hellp but think of the refrigerator.

Quote:

Originally Posted by John UK

It's easy to check if the light is on all the time.
Climb into the trunk and shut the lid. Just make sure a (good) friend is there to let you out again.
John

also there is an emergency trunk release in the trunk. and it glows in the dark.

RR

ATX25RS · 07-01-2005, 01:13 PM

yep.....scariest thing is when it doesnt work though.....my fat ass cant fit through the pass through

06-30-2005, 04:01 AM	#1
pico Scooby Newbie Member#: 5254 Join Date: Mar 2001 Location: Santa Clarita, CA Vehicle: 01 WRX PSM	Stupid light bulb...... My battery was drained last week, I took out the battery and let autozone recharge it for me. Then i measured the reisistance between the 2 cables and it show 3.7ohm!!! I checked all the fuse and they're all fine and after 2hrs of peek and poke finally i find out that my trunk light bulb was shorted!! I always thought light bulb will be opened rather than shorted when they goes bad..... * Registered users of the site do not see these ads.

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06-30-2005, 09:04 AM	#2
Mulder Trust no one Moderator Member#: 11170 Join Date: Oct 2001 Chapter/Region: Tri-State Location: NYC Vehicle: 02 WRX 05 GTO/11 Sonata(!)	That is actually a normal resistance reading for a light bulb. The problem isn't the bulb itself, but that it is connected when the trunk is closed. Your problem actually lies with the trunk light switch, rather than the bulb. The switch is either defective or not adjusted properly. You can confirm this by looking through the rear seat pass-through when the trunk is closed, if the light is still on you'll see it. If it is proceed to either adjust or replace the switch.

06-30-2005, 03:12 PM	#3
pico Scooby Newbie Member#: 5254 Join Date: Mar 2001 Location: Santa Clarita, CA Vehicle: 01 WRX PSM	thats true......... but isn't 3.7ohm kinda low??? which means it draws >3 amps when its on..... thats about 40W?!

06-30-2005, 04:21 PM	#4
Mulder Trust no one Moderator Member#: 11170 Join Date: Oct 2001 Chapter/Region: Tri-State Location: NYC Vehicle: 02 WRX 05 GTO/11 Sonata(!)	The resistance of the filament increases when it heats up. So did you check your switch?

06-30-2005, 04:34 PM	#5
avk Scooby Specialist Member#: 17252 Join Date: Apr 2002 Chapter/Region: Tri-State Location: NJ Vehicle: '06 WX8 59E	The resistance goes up some 10 times, so the power will be in 5W range which is about right.

06-30-2005, 09:41 PM	#6
pico Scooby Newbie Member#: 5254 Join Date: Mar 2001 Location: Santa Clarita, CA Vehicle: 01 WRX PSM	ic, I haven't has time to check it yet. but let say if the switch is bad, which means i has it on for a few days, will it drain my battery out? or do u think i have some other stuff thats drawing power as well??? I guess the light buld is smart and i'm the stupid one...

06-30-2005, 09:49 PM	#7
Mulder Trust no one Moderator Member#: 11170 Join Date: Oct 2001 Chapter/Region: Tri-State Location: NYC Vehicle: 02 WRX 05 GTO/11 Sonata(!)	Yes a stuck-on trunk light will drain the battery if left alone for a few days. Exactly how long it will take depends on the battery condition and state of charge(may not be too good if it's been discharged already). If you can't get to it right away, just take the bulb out. Another sign it's been on is if you open the trunk to pull the bulb, and it feels very hot from being on a long time.

07-01-2005, 04:16 AM	#8
John UK Scooby Newbie Member#: 81042 Join Date: Feb 2005 Location: Oxford UK Vehicle: 2000 5 door turbo Silver	It's easy to check if the light is on all the time. Climb into the trunk and shut the lid. . . . . Just make sure a (good) friend is there to let you out again. John

07-01-2005, 06:14 AM	#9
Mulder Trust no one Moderator Member#: 11170 Join Date: Oct 2001 Chapter/Region: Tri-State Location: NYC Vehicle: 02 WRX 05 GTO/11 Sonata(!)	^ Not necessary with the pass-through.

07-01-2005, 01:13 PM	#11
ATX25RS Scooby Guru Member#: 4597 Join Date: Mar 2001 Chapter/Region: TXIC Location: Laredo, Texas Vehicle: 2011 Mitsu Outlander Sport (Ex-Suby owner X3)	yep.....scariest thing is when it doesnt work though.....my fat ass cant fit through the pass through