ECU Fuse Keeps Blowing after Trackday - No CEL - TT

Originally Posted by Jhill

Ok so I’m a bit out of practice since I’ve been out of the industry for about 6 or 7 years now but it sounds like your chasing an intermittent short with a fuse that feeds a bunch of parallel circuits. It sounds like it’s at least consistent enough you can get it to blow reliably so that’s a good thing. So what you could do is use a recording dmm or scope with an amp clamp on and you’ll have to monitor each branch of the circuit while the fuse blows to see which one is spiking.

The other option which I’ve had to do for a customer that would blow one fuse every 4-6 months so very intermittent and that fuse fed 5 wires which then each split into 3 other parallel circuits so there was no way I was going to find it. In a situation like that or what you can do since most likely don’t have a way to record amperage is go get a bunch of in line fuse holders and fuses and you’ll have to cut and wire in the in line fuses on every branch that fuse feeds. Once you have the branch with the fuse that pops you’ll have better isolated the components and wiring path you need to inspect (took a while but finally found a hairline crack in a wire that would intermittently touch the window regulator channel).