Running neons in my truck and I bought some extra wire. I bought 18 gauge but the wire on the neons is slightly smaller, maybe 20 gauge? The 18 gauge runs a few feet to the neons from the power source (12 volt in the ignition harness) and a few feet for the ground. Will it make a difference using different size gauges or should I go pick up some smaller wire? I don't want to blow the ignition fuse again and have my truck immobile once again . I didn't finish them up yet since I realized this could be a problem. Thanks!

 

Generally speaking, a larger wire will have less resistance, so I'd have little problem with running what in effect is a better conductor for a few feet. Make sure you make a clean and insulated splice though. Now, if you were talking about a smaller conductor, we'd have a bigger problem.

Speaking of problems, you mentioned that you're drawing power from your ignition harnness and you'd blown a fuse there. Whoa! Now we have a problem. I'd suggest that you run power (with an in-line fuse) from a proper source (like your fuse box or battery) instead. Again, don't just hack in there. Use an approved method like Add-a-Circuit. If you just tapped into your harness, you're asking for much bigger problems.

 

I used a t-tap to tap into the ignition harness. Somebody at fordf150.net recommended this approach. Will the t-tap cause a problem or just splicing would? I know I blew a fuse but that was when I tried to wire the ground for the bulb inside the switch and didn't properly ground it...then there was a spark and the truck wouldn't start. I found the fuse and replaced it. What bigger problems could come from this?

 

The electrical systems on all new vehicles are designed so close to their practical limits these days that virtually any change can burn you. On top of that, I have this personal thing about tapping into any major harness - like the ignition harness. For one thing, it will give your dealer an easy reason to void your warranty. (They don't need much of a reason these days.) For another thing, you risk ruining something big (and expensive) just to get something little - like neon lighting. Just my personal opinion, but I wire all of my stuff (and everything I do for other folks) very conservatively - which means it takes more time and maybe costs just a bit more. Then again, I've never fried anything bigger than a fuse.

 

Thanks for the info. I will definitely take your approach in the future. I didn't know how easily something small like this could turn into something big. My warranty has already ended, thats the only reason I'm making any modifications to my truck whatsoever. Needless to say I was freaking out when my truck wouldn't start. Thanks again! I'll be verrry careful with that! J/w what kind of engineer are you? I saw it as your occupation in your profile. I'm going to school for software engineering right now, I just changed my major from mechanical engineering.

 

Mechanical Engineer