pop goes the fuse

[audiman]

right more help needed please

i changed the battery from the one that was on it which was not the correct battery was far too small for the battery tray I then got the engine warm as i was not sure if the electric fans were working my guess was right they did not kick switched off and had a look and there were a few fuses that had popped 1 i am pretty sure was the fuse for the electic fan circuit which at some point in the patrols life has been put through a bypass with a switch in the cab to kick in the fans
one of the other fuses that had popped was the cig lighter which is great cos now my sat nav works (i dont smoke)

the 3rd fuse goes to some diy wiring into a relay i assume something to do with the immobiliser and terminates on the live of the battery terminal and is a 30 amp fuse as soon as you plug any size fuse into the fuse holder in this diy wiring it pops i thought that the battery i had which was secondhand off a mate might be faulty so i put the smaller battery back on last night fuse pops as soon as inserted
some of the wiring was only twisted together so i made the connections good with electrial connectors but this has made no differencne as the fuse is on the live side once its pops i get no feed to the fuel pump so although the engine turns overs it will not fire
so could the relay in this circuit be faulty and can anyone point me in the right direction for a wiring diagram for a 160/ 260 series patrol just in case i am missing something really simple it a l28 engine with a carb 92 vintage

regards

Lee

[MudRunnerTD]

The 3rd fuse circuit has a dead short mate. If it is dodgy wiring then do yourself a favour and trace back each wire and rip out anything that has no purpose. It's in the way, looks messy and offers somewhere to fail.

Work backwards and pull it out if its not being used, if it is in use and been done badly then rip out and replace with wiring you can trust.

You will thank yourself and learn about your car.

Anything that dodgy brothers have put in will not be in a wiring diagram bud so thre will be little help.

Isolate the rubbish and start from there.

Good luck and have fun

[NissanGQ4.2]

Lee, I have moved your thread under: Mechanical - Auto Electrical

Cheers

Toddie

[Yendor]

I don't think that 3rd fuse will be for your immobiliser, 30 amp fuse is too big for this. It could possible be for driving lights or even for the fuel pump.

You will need to do as suggested and follow the wire and see where it goes, looking for any signs of damage as you go.

[BearGUST]

The good news is that it pops the fuse straight away, makes it much easier to diagnose!
Disconnect a few bits of the aftermarket wiring, when the fuse stops blowing you know you've found where the problem is...