Testing an H3 Bulb
Printed From: the12volt.com
Forum Name: Lights, Neon, LEDs, HIDs
Forum Discription: Under Car Lighting, Strobe Lights, Fog Lights, Headlights, HIDs, DRL, Tail Lights, Brake Lights, Dashboard Lights, WigWag, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=76134
Printed Date: May 10, 2025 at 5:36 AM
Topic: Testing an H3 Bulb
Posted By: slvr-bullet
Subject: Testing an H3 Bulb
Date Posted: April 12, 2006 at 3:47 PM
I purchased some OEM fog lights.
Now I want to test them out first before I install them but I can't get it to work.
I'm using a variable DC power supply and when I hook up the +/- (12v) to either the bulb or the wiring harness connector, the voltage just drops to zero.
The front panel of the power supply goes (+/-) (ground) (+/-)
What am I doing wrong?
Replies:
Posted By: Mad Scientists
Date Posted: April 12, 2006 at 4:17 PM
I'd suspect the power supply can't output what the bulb needs.. what's the rating on the power supply? Jim
Posted By: slvr-bullet
Date Posted: April 12, 2006 at 4:26 PM
Mad Scientists wrote:
I'd suspect the power supply can't output what the bulb needs.. what's the rating on the power supply?
Jim
input = 120v, 60Hz, 80W
output = 0-15v, 1A max.
The bulb is 12v, 55W
Posted By: slvr-bullet
Date Posted: April 12, 2006 at 5:35 PM
Finaly got it to work.
Hooked it up to one of those booster packs.
Thanks for your help tho ;)
Posted By: ff-mike
Date Posted: April 14, 2006 at 10:35 AM
You can use a multimeter to check the bulbs for continuity, or resistance. They measure around 2-3 ohms.
A 12v 55w lamp uses around 4.5amps of current, that is why your 1a power supply did nothing
Posted By: slvr-bullet
Date Posted: April 14, 2006 at 8:38 PM
Yah, I figured that out after I did I=P/V 
Posted By: skyford
Date Posted: May 10, 2006 at 4:33 AM
Can you show me a photo of your H3 bulbs?
 ------------- HID-High Intensity Discharge
Xenon Lamp for your cars
Posted By: ff-mike
Date Posted: May 10, 2006 at 9:12 AM
That is not an H3
Posted By: slvr-bullet
Date Posted: May 10, 2006 at 11:50 AM
Yah, that looks more lid a HID bulb.
This is a H3 bulb

Posted By: skyford
Date Posted: May 17, 2006 at 12:28 AM
Yes, this is just the bulb, and here is a ballast. Two bulbs and two ballasts are included in one unit conversion kits.
------------- HID-High Intensity Discharge
Xenon Lamp for your cars
Posted By: slvr-bullet
Date Posted: May 17, 2006 at 7:38 AM
skyford wrote:
Yes, this is just the bulb, and here is a ballast. Two bulbs and two ballasts are included in one unit conversion kits.
And the reason for posting HID bulbs and ballasts is?
Posted By: ff-mike
Date Posted: May 17, 2006 at 10:30 AM
https://lfd.lannonfire.com/forums/12volt/H3_Comparison.png
This is why HID bulbs in a filament (eg halogen, incandescant)lamp is a bad proposition.
#1 The HID light source is on a different axis
#2 The HID light source is curved, not straight
Posted By: slvr-bullet
Date Posted: May 17, 2006 at 10:59 AM
Yes I know that Mike but my topic was/is about testing H3 bulbs, nothing about HID bulbs/ballasts.
But anyway, the problem was solved and I appreciate everyone's help 
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