blowing fuses

[AaronStath]

hey fellas, im very much a rookie with no experience with cars except for youtube tutorials. i know stupid idea to play around with but it was a sunday job i thought i could do before a little camp trip.
so..
I’ve installed a kickass duel battery plug n play system in the tray of my 2016 nissan nav. the link to all the specs is
https://www.australiandirect.com.au...MI3oPoqfen9AIVDSUrCh0-kwkTEAQYASABEgLHb_D_BwE
so i have installed the battery in the battery tray with the dcdc charger and the low voltage disconnect connected to the outside of the battery tray.
i have run out the cable from the starter battery with a 80 amp fuse under the car to the ute tray where the battery is kept
i used the ignition cable to run through the fire wall to a piggy bag fuse hooked into the heated seats spot which is a 10 amp as i dont have heated seats in my model nav
i hooked up the dcdc charger to the aux battery.
i hooked up the aux battery to the low voltage disconnect with an 40 amp fuse and the 80L engel fridge up to the low voltage disconnect aswell
everything was running sweet until the voltage dropped to 12.5 and it cut the aux battery off.
which it says on the instructions it cuts off at 11volts.
i noticed when i went to drive the car that the reverse lights were on and the car wasnt powered
i started the car and noticed the reverse camera wasnt working
the traction light on the dash was on
and the left blinker didnt work.
so i disconnected the entire duel battery set up and started looking for blown fuses and found a blown 10amp fuse linked to the reverse lamp
so i changed it out started the car and it blow straight away.
i have no idea whats going on??

 

[Old.Tony]

Have you removed the wire that you ran through the firewall? Just disconnect it from inside and outside, no need to pull it out just yet.

The odd behaviour from other things like traction control and indicators is more like a crushed wiring loom, though. They are unrelated separate systems so it's probably some wiring loom in the engine bay that's been snagged somewhere, although it's always possible that it's the cable run under the car to the rear that's copped a whack or something.

 

[AaronStath]

Have you removed the wire that you ran through the firewall? Just disconnect it from inside and outside, no need to pull it out just yet.

The odd behaviour from other things like traction control and indicators is more like a crushed wiring loom, though. They are unrelated separate systems so it's probably some wiring loom in the engine bay that's been snagged somewhere, although it's always possible that it's the cable run under the car to the rear that's copped a whack or something.

Cheers for the reply.
yeah I’ve disconnected the ignition wire running through the fire wall to the fuse box and I have disconnected the wire from the crank battery to the aux battery. I haven’t tested another fuse just yet as I thought I’d wait for a reply in case I caused further damage.
I’ll get under the car tomorrow and trace the wire I run out to see if I have damaged any other cable or "thing" under there.
i was also thinking a trip straight to nissan in the morning for them to have alook and repair whats happened. then to the auto electricians to book the duel battery set up.

 

[Old.Tony]

I'd hold off on the trip to Nissan, they could easily charge you an absolute fortune for that one. Part of their process is to "follow the manual" and they do it to the letter. You might think your SCV needs replacing, and that's precisely what it is, and in reality they only need to provide that ($240) and about an hour of labour (if that). But the book says pull the injectors, then the rail, then the pump and once they've replaced the pump (where the SCV sits) it magically works, they get a big happy and hand you the bill for injectors ($4K), fuel rail ($1.6K) and pump ($4K) plus labour ... they do this quite a bit. So I'd look at where you've been first, because you will probably save yourself heaps. Of course, you might not find it and have to take it to someone (auto electrician could also find the fault and won't be replacing your entire wiring loom to do it).

Electrics are fairly simple. If you're blowing fuses, there's something that's increasing the load on that fuse. Directly connecting positive to negative will do that real fast, but it could also be an additional load on the system: imagine your headlights, which normally are 60W peak each. That's 5 amps. You have a 20A headlight fuse, which services both headlights.

But, because you're a good mate, I come around and help ya out fitting your 9" 130W halogen landing lights you scored out of a Boeing 747 that was nicked and dumped behind the pub. I simply tap directly into the back of the headlight and draw the power from that ... now that fuse is not only feeding 120W of main headlights, but another 260W of bunny-frying driving lights. The fuse will blow. (for what it's worth, I've drawn diagrams on how to do this properly using relays in the past, they're here somewhere, but I'm trying to show how things can break without shorting out).

Other electrical gremlins can appear, like the stereo-instrument cluster issue, where the earth point to both is shared and becomes faulty, causing the stereo to earth through the instrument cluster and cause random problems with other systems that the cluster is connected to (there's a lot!). It's fixed by earthing the stereo separately, but the point is that one of those other systems has NOTHING to do with the stereo! Which reminds me, check yours ... the stereo uses the reversing signal.

 

[AaronStath]

Have you removed the wire that you ran through the firewall? Just disconnect it from inside and outside, no need to pull it out just yet.

The odd behaviour from other things like traction control and indicators is more like a crushed wiring loom, though. They are unrelated separate systems so it's probably some wiring loom in the engine bay that's been snagged somewhere, although it's always possible that it's the cable run under the car to the rear that's copped a whack or something.

I'd hold off on the trip to Nissan, they could easily charge you an absolute fortune for that one. Part of their process is to "follow the manual" and they do it to the letter. You might think your SCV needs replacing, and that's precisely what it is, and in reality they only need to provide that ($240) and about an hour of labour (if that). But the book says pull the injectors, then the rail, then the pump and once they've replaced the pump (where the SCV sits) it magically works, they get a big happy and hand you the bill for injectors ($4K), fuel rail ($1.6K) and pump ($4K) plus labour ... they do this quite a bit. So I'd look at where you've been first, because you will probably save yourself heaps. Of course, you might not find it and have to take it to someone (auto electrician could also find the fault and won't be replacing your entire wiring loom to do it).

Electrics are fairly simple. If you're blowing fuses, there's something that's increasing the load on that fuse. Directly connecting positive to negative will do that real fast, but it could also be an additional load on the system: imagine your headlights, which normally are 60W peak each. That's 5 amps. You have a 20A headlight fuse, which services both headlights.

But, because you're a good mate, I come around and help ya out fitting your 9" 130W halogen landing lights you scored out of a Boeing 747 that was nicked and dumped behind the pub. I simply tap directly into the back of the headlight and draw the power from that ... now that fuse is not only feeding 120W of main headlights, but another 260W of bunny-frying driving lights. The fuse will blow. (for what it's worth, I've drawn diagrams on how to do this properly using relays in the past, they're here somewhere, but I'm trying to show how things can break without shorting out).

Other electrical gremlins can appear, like the stereo-instrument cluster issue, where the earth point to both is shared and becomes faulty, causing the stereo to earth through the instrument cluster and cause random problems with other systems that the cluster is connected to (there's a lot!). It's fixed by earthing the stereo separately, but the point is that one of those other systems has NOTHING to do with the stereo! Which reminds me, check yours ... the stereo uses the reversing signal.

Hey mate thanks heaps for that reply, I’ve been out and traced where I’ve been and gone back to the battery terminals everything is ok
So I’ve tested the battery and got 12.56v
I’ve then disconnected the terminals and tested the negative Battery clamp with the positive on my multimeter and the negative terminal on the battery with the Meg on the multimeter and it’s come up with 0.000. I’ve read a page on a web site and it said by doing that the volts should read within 0.005 of the reading I got from the battery. If this is correct I think I need a new earth strap

 

[Old.Tony]

Ok, let me be clear on this: you disconnected the battery leads from the battery and then measured the voltage across the battery cables or the battery itself?

If the battery is not connected to the car, you should get 0 volts (plus or minus any error in the multimeter and any residual voltage stored by the ECU or other small computers on board). The battery might show a very slightly higher voltage (if the multimeter is sensitive enough to show it) when the small parasitic draw on the battery is removed.

Battery connections are often the cause of silly and sometimes unfathomable problems, cleaning the terminals and the negative cable to the engine is sometimes all that's needed to fix it. Not sure that's the case here.

I have another suggestion that might help (and this one will appear confusing but there's a reason for it). Undo both tail lights, remove the plugs and pull all the bulbs. Clean it all, reinstall and try again.

We had a problem with our car where corrosion in one of the bulb sockets on the left hand tail light caused power to feed across from reverse to the indicator circuit and because the ground (negative) was drawn through the parker circuit, nothing worked. Cleaned the bulb socket (and bulb) and it all worked properly again.

 

[AaronStath]

Ok, let me be clear on this: you disconnected the battery leads from the battery and then measured the voltage across the battery cables or the battery itself?

If the battery is not connected to the car, you should get 0 volts (plus or minus any error in the multimeter and any residual voltage stored by the ECU or other small computers on board). The battery might show a very slightly higher voltage (if the multimeter is sensitive enough to show it) when the small parasitic draw on the battery is removed.

Battery connections are often the cause of silly and sometimes unfathomable problems, cleaning the terminals and the negative cable to the engine is sometimes all that's needed to fix it. Not sure that's the case here.

I have another suggestion that might help (and this one will appear confusing but there's a reason for it). Undo both tail lights, remove the plugs and pull all the bulbs. Clean it all, reinstall and try again.

We had a problem with our car where corrosion in one of the bulb sockets on the left hand tail light caused power to feed across from reverse to the indicator circuit and because the ground (negative) was drawn through the parker circuit, nothing worked. Cleaned the bulb socket (and bulb) and it all worked properly again.

Hey mate I ended up just taking it to the auto electricians and they found that the main harness running to the rear of the vehicle has burnt wire running through. They said it will require a new harness and possible issues with BCM after wiring repairs carried out.

 

[Old.Tony]

Wow, how did that happen?

The BCM may have an internal fuse (I think it has a 10A one on its circuit board) so it may have survived. I guess time will tell. Any idea how far the burning went? Are there many wires involved? Can the burnt wires be replaced?

 

[AaronStath]

Wow, how did that happen?

The BCM may have an internal fuse (I think it has a 10A one on its circuit board) so it may have survived. I guess time will tell. Any idea how far the burning went? Are there many wires involved? Can the burnt wires be replaced?

He said he doesn’t know why or how it happened cause if it was something I did then why are the fuses to the fuel battery system unblown.
not sure how far it’s actually fried in the cable but he said he stripped it 2 foot in and it was still fried.
I’ve organised a second auto electrician to look at it on the 10th so hopefully he says exactly what needs to be done and I’ll just have to cop the bill.
thanks heaps for your help so far mate

 

[Old.Tony]

He said he doesn’t know why or how it happened cause if it was something I did then why are the fuses to the fuel battery system unblown.
not sure how far it’s actually fried in the cable but he said he stripped it 2 foot in and it was still fried.
I’ve organised a second auto electrician to look at it on the 10th so hopefully he says exactly what needs to be done and I’ll just have to cop the bill.
thanks heaps for your help so far mate

No worries, happy to offer what help I can via a forum!

Let's hope the damage didn't go too much further. Good luck!

 

[AngryWO2]

Ok, let me be clear on this: you disconnected the battery leads from the battery and then measured the voltage across the battery cables or the battery itself?

If the battery is not connected to the car, you should get 0 volts (plus or minus any error in the multimeter and any residual voltage stored by the ECU or other small computers on board). The battery might show a very slightly higher voltage (if the multimeter is sensitive enough to show it) when the small parasitic draw on the battery is removed.

Battery connections are often the cause of silly and sometimes unfathomable problems, cleaning the terminals and the negative cable to the engine is sometimes all that's needed to fix it. Not sure that's the case here.

I have another suggestion that might help (and this one will appear confusing but there's a reason for it). Undo both tail lights, remove the plugs and pull all the bulbs. Clean it all, reinstall and try again.

We had a problem with our car where corrosion in one of the bulb sockets on the left hand tail light caused power to feed across from reverse to the indicator circuit and because the ground (negative) was drawn through the parker circuit, nothing worked. Cleaned the bulb socket (and bulb) and it all worked properly again.

I had the same problem with the Parker lights in the bullbar, had a hair line crack allowing water in. Fixed it all problem solved.