I was installing the lighting switch for my new AutoMeter guages last night and I came across a strange bug. I'm not an electronics expert, so I figured I'd ask you guys who know.

Here's the setup...(sorry if I use any wrong terms)...

From the battery I have a 12V line running to a standard relay inside of the car. Its grounded, get the on/off signal from the clock dimmer and has an output wire going to my switches.

I put a switch on a few weeks ago for interior neon and everything worked perfectly! No problems at all.

So, yesterday I added another switch. I got the supply volts from the output line from the relay, spliced the ground into the ground on the first switch, and sent the output of the switch to the guages.

Now, when I turn the lights on, if the switch is in the ON position, everything works great! The guage lights turn on, and I couldn't be happier. However, once I turn the switch off, it blows a fues (Don't remember the exact name for it, but its the interior illumination fuse). If the switch is in the OFF position and I turn the lights on, the fuse blows.

Any ideas? I also tried taking the switch out and connecting the supply to the switch with the output line from the switch (basically bypassing it) and the same fuse blew.

 

Somewhere your power wire is touching ground and causing the fuse to blow. It can be something as minute as a little piece of a frayed wire, so maybe look where you spliced the switch or if you didn't cover everything exposed with heatshrink or electrical tape do that.

 

The power to the switch, or from the switch to the lights?

 

most likely it would be on the switch to the lights since those are all connected causing the blown fuse. And it actually could be the other way as well, but I think that it would be more like the first way I said.