Under-Dash Lighting

I am going to install some type of lighting under the dash of a 1995 Chrysler Concorde. Either LED or Neon, will I need a fuse? Is a fuse needed for a relay connected to 12v constant? Also, is the 12v constant wire fused itself? Thank you for the comments. Suggestions are also appreciated.

There are two answers to your question.  Yes and  No.

Unless you hook your power wire up directly to the battery you don't technically need a fuse, however it is a VERY good idea to add one.  All the power wires found in the vehicle will be fused already, so you can rely on the OEM fuses.  However, if you have a 60A fuse on your power wire, and your neon transfomer starts to fail and pulls 25A the fuse won't blow, but the wire will most likely catch on fire and burn your car.

So, you don't need a fuse, but fuses are there to protect your CAR and not necesarrily the device you are hooking up. 

Also, if you size your fuse smaller then the fuse that protects your 12vdc source then you won't have to worry as much about blowing OEM fuses if your wiring faults. 

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Kevin Pierson

Thank you for your quick response! I now feel comfortable with my install. However, I have a relay with a wire directly connected to a 12v constant. Is there a need for a fuse since it is only an electro magnet?

Well, the load of the wire isn't important when the wire you added gets shorted to ground.  At that point, the wire will draw as much current as is availible from the battery (800 amps or so in normal cases).  Like I said, the fuse is there to protect the car, not the device at the end of the wire.

Is there a reason you don't want to use a fuse?

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Kevin Pierson

i designed led underlighting for my car, a wire shorted, and my fuse was so high amp the wire melted then the fuse blew. i use a 3amp ato now. would you "get it on" with a random person without protection? probably not, why? too much risk. would you want to risk a wire shorting and heating up to the point of burning up your large investment? fuses were made for a reason, its to protect you from loss, just use it, best advice.

Good advice!

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Kevin Pierson

Ya know, thats a good point. Here's another one. A fuse costs 10 cents, a car $21,000 which is cheaper?

I ditched the fuse when I wired in my neons but I did so halfheartedly. I'm still thinking of a way to put it back into the mix, possibly with a pre-made fuse holder.