*HELP* ECU IG fuse blowing

[AmeriKUN26]

Need some help guys, the Lux is my daily driver right now. Long story short, was driving to work today and lost power windows speedo etc. did some searching and found the ECU IG fuse blown. Replaced it and made it about halfway home before it blew again. Nothing to report operating when it blew, no lights, reversing, not towing etc. got home and it would blow the fuse immediately upon engine start.

Checked and noticed alternator wasn't charging so I suspected the fusible link, opened it up and noticed it has been bridged with solder at some point (SA market) after it cooled off I started it and put the ECU IG fuse in and it's all good and charging so maybe the alternator isn't hosed, hard to say how they blew the fusible link. Ordered a new fusible link assembly from Aus.

This leaves me with why the ECU IG fuse is blowing, I've looked at a lot of old threads and checked my trailer plug wiring and everything I can think of. Can anyone offer a good way to narrow down the likely short? It's my daily right now and obviously I'm on my own with a long lead time on parts. Cheers

[ptommo59]

The Fusible link would have been blown if they connected the battery reverse polarity as the rectifier diodes in the alternator would have shorted it to ground.

The 10A ECU-IG & Gauge Fuse is connected to lots of circuits so will be a pain to isolate unless you can pin down what action consistently causes it to blow (or what doesn't)
This links is for the Vigo (N70) wiring diagrams so might help.

Start on Page 191 in Section J and it will point you to each of the circuits that are associated with the fuse. Try operating the function that uses the fuse (if this is possible) and see if you can make it consistently blow with one of them and that most likely is it.
But if its a wiring rub through and intermittently shorting it will be a pain to find depending where its located.

https://www.tuningconcepts.com/Cars/Hil ... iagram.pdf

[AmeriKUN26]

The Fusible link would have been blown if they connected the battery reverse polarity as the rectifier diodes in the alternator would have shorted it to ground.

The 10A ECU-IG & Gauge Fuse is connected to lots of circuits so will be a pain to isolate unless you can pin down what action consistently causes it to blow (or what doesn't)
This links is for the Vigo (N70) wiring diagrams so might help.

Start on Page 191 in Section J and it will point you to each of the circuits that are associated with the fuse. Try operating the function that uses the fuse (if this is possible) and see if you can make it consistently blow with one of them and that most likely is it.
But if its a wiring rub through and intermittently shorting it will be a pain to find depending where its located.

https://www.tuningconcepts.com/Cars/Hil ... iagram.pdf

Thanks for the reply, I've downloaded the manual and printed each diagram that is fed by the ECU-IG breaker and sorted them in order of likelihood. Based on the timing of blown fuses so far I think it's an intermittent short to ground. Worth noting is the fuse (when I had just returned home warmed up) was blowing immediately and energetically upon engine starting.

I will attempt to operate each of the associated systems to see if I can induce a fault this evening. Also hoping I can find good points to disconnect wiring harnesses to hopefully at least narrow down the search. Truly a staggering amount of wiring associated with this fuse. I will continue to update, cheers

[AmeriKUN26]

May have lucked out today, poking around underneath and it looks like the exhaust heatshield on the RH side of the transmission tailshaft was barely rubbing a wire there (probably the speed sensor). I repaired it and will report back here if it's NOT fixed for future users.