Festoon Bulbs

[kcpth]

Hey guys, i have a question for you. I just recently bought 2 festoon bulb from superbrightleds.com and i tried to install it in the dome light (right behind my head or is it called the courtesy light) of my g/f's 92ES. It uses a festoon bulb. For some reason, whenever i install it, and try turning it on, it blows a fuse #20. I replace it and i tried a 2nd bulb that i bought and it blew the fuse again.

Now i called the rep @ superbrighleds and he said he's not sure y it is blowing the fuse either. He said it draws a fraction of the current from the original bulb. Even if i were to install the bulb improperly due to it being polarized, it just wouldn't light up not blow a fuse.

Now i have an Electrical Multi-Meter. What do you suggest i test? If you don't mind me asking too... how to test it. I dont' really know how to use a Multimeter. I think i have to switch it to DC side... but is it on 10V or 50V? Should i test the bulb and the car where the bulb goes in? If i test the car which setting on the multimeter should i leave it on too?

I also bought their BA9's and they work fine. It's just their Festoon bulbs that seem to b giving me a problem.

Wut happens if i put a bigger fuse in there? What will that do?

Thanks for the help.

[bartkat]

Maybe the bulb has such low resitance that the fuse thinks it's a dead short.

What happens when you use a good OEM bulb?

[kcpth]

i havne't gotten a chance to put them in yet b/c i blew both the original fuse n the spare... now i have to go out n buy a new pack of fuses. Right after my 1:30-4:30 lab class. Chem is driving me insane.

[kcpth]

i did put the original bulb back in... n it does work and does light up.

i tried using the multimeter on the festoon bulb, i went through all of the settings... nothing showed up. What does that mean? No current running through? If there isn't any current running through, y would it blow the fuse? What r the chances two different festoon bulbs blew?

I thought the BA9's LED's were going to be bright, but they weren't as bright as i thought.

[bartkat]

i did put the original bulb back in... n it does work and does light up.

i tried using the multimeter on the festoon bulb, i went through all of the settings... nothing showed up.  What does that mean?  No current running through?  If there isn't any current running through, y would it blow the fuse?  What r the chances two different festoon bulbs blew?

I thought the BA9's LED's were going to be bright, but they weren't as bright as i thought.

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Are you sure that reversing polarity wont blow the LED?

I would check for continuity and resistance across the LED, but then I'm not a mult-meter guy. Compare the resistance across a LED bulb to that of your stock bulb.

LED's aren't as bright as filament bulbs. That's why they have to use mulitiple LED's in tail lights, etc, to get similar brightness. Same thing for flashlights. The website from the place you got your bulbs also tells you that they aren't as bright.

[kcpth]

Thanks for the help bartkat. Well i did try with the multimeter and i tried switching the ends of the metal prongs nothing showed up. So i don't know if it blows the whole reverse polarity. But what puzzles me is blowing the fuse.

Yea... i assumed they were going to b bright which was my fault.

[CUMan]

I am probably going to show my ignorance on using a multi-meter, but it appears from your first post that you are not using the correct setting on the meter.

You would not use a DC voltage setting to check whether a bulb is good. This setting would be used to determine the amount of voltage that is available at the location in the car where the bulb is being plugged in.

The setting to check whether or not a bulb is good would be the ohm setting. This is designated on a multi-meter with the upside-down u symbol. When you turn your multi-meter on and turn the selector to the ohm settings, the display should show a "1". This indicates no continuity. If you touch the two leads together, the display should go to "0". The "0" indicates no resistance. If you touch one lead to one of the contact points on a bulb and the other lead to the other contact point, you should get a "0" reading if the bulb is good, i.e., it has continuity. A bad bulb, just like a blown fuse, should give you a "1" reading, which indicates no continuity.

If a bulb is blowing a fuse, it would seem to me that it is drawing more current than the circuit can provide.

[kcpth]

First... i'd like to say sorry for the quality of the picture. I used my camera phone to take it.

Thanks for answering my post too. I'm assuming you mean to test it this way right. I did have it set in the Ohms section.

The needle did not move at all. So that means it's a busted bulb right? Hmmm... even if the bulb is busted... it would and could blow a fuse? But the guy said it shouldn't b drawing more power than the stock OEM's. Perhaps i got the wrong bulb? Well all i know the bulb is a 12V. Should i have bought a 6V? That would draw less current right? Tomorrow i will try and test it out on the OEM version to see what i get.

[CUMan]

I assumed you had the digital type multi-meter. You have the old type with a needle.

What happens when you touch the two leads together? The result should be the same as when you touch the two ends of the bulb - if the bulb is good.

I suppose the bulbs could have some kind of internal short circuit that would cause a fuse to blow.

Your car has a 12 volt electrical system, so you should only use 12 volt bulbs. I would assume that a 6 volt bulb would blow as soon as you installed it.

Sorry I can't be more help. I am not familiar with the type bulbs you are attempting to use.

[kcpth]

Hahaha, thank you very much for your info.

Yup i am using the old multimeter. When i touch the two leads together, nothing shows up, and according to the Ohms part, it is on "0". So i suppose there is a short somewhere inside it. I'll have to call them and ask them to return it.

Thanks for everyone's help and advice.