Car ecu blown? urgent

[Barton1806]

I have finished fitting a cage to my car and I now have no lights on dash ignition etc, also my hazards do not work but my immobilizer light is very dim. The battery is showing 12V with a meter at the terminals in the boot. but at the connector post under the bonnet is showing 2.1V I have had a problem with it having power but all ancillaries not working before and it was down to the relays in the black box under the glovebox being badly connected. I was using the wipers and lights were flashing etc so pushed the relays in and they worked fine. then a friend went to connect the battery and the spanner earth out on the battery cage then a big spark and it has now died.

Have I killed my ecu or is there a fuse hidden somewhere as all my fuses are in one piece on passenger side and under bonnet etc.

regards

 

[Pauleds]

If you are only reading 2.1v under the bonnet from the power cable to your battery in the boot then the power cable or battery earth is the problem as the battery has the correct voltage.

 

[lemonnobby]

There is a big maxi fuse By the battery terminal it looks just like a square thing

 

[lemonnobby]

If that's blown you will have to solder it back together.