No power at all

[v840]

Just bought a sierra. Went to pick it up and the previous owner had lost the keys
Took the back off the ignition switch so I could start it but the screwdriver I was using brushed across two wires (I dont know which two, it was dark) and arced. After that the entire car has no electrics at all . No lights, hazards, dash lights, nothing.

Ive been told that Ive done either the main engine fusible link or the ecu but after spending all day today underneath following wires between the battery (which is still reading 13v on the multi meter) and the starter and the alternator etc. I cant for the life of me find the main engine fuse.

Does anyone know where I might find it? Or if it definitely has one at all? How do I check if the ecu is cactus? The engine is a 4AGE if that helps.

Could it be anything else that has completely escaped me?

I also checked every fuse in the car and they are all fine.

Cheers.

[-Scott-]

Sometimes the main fusible link looks like a (short) piece of normal wire, often with in-line plugs at each end. It may not show outward signs of being damaged.

Start using your multimeter to follow wires away from your positive terminal. Make sure you switch your headlights on first; if there's no electrical load you may not see a voltage drop across a high-resistance link.

Good luck,

Scott

[DamTriton]

Agree with above, but note that unless the Sierra has had an engine transplant, it will not have an ECU. This would not cause all the electrics to go out anyway.

Try asking in the Zook section, there will be a few more knowledgable ppl about the specifics there

[v840]

unless the Sierra has had an engine transplant, it will not have an ECU.

The engine is a 4AGE if that helps.

Thanks for your help though. If a buggered ECU wouldnt mess with all the electrics does that only leave a fusible link? I looked everywhere for that sucker.....

[guzzla]

maybe it was stuffed to start with and you feel like it was your fault surely a quick arc wouldnt harm it

bit sus that he lost the keys just when you came to pick it up isnt it

ive just experienced loosing all ignition switching after welding to my mates troopy. was starting to stress as i had disconnected the terminals and alternator b4 welding...... then i remembered about the alarm

good luck

[v840]

The lights were working when we got there as I tested them out and Id heard it running previously so I know its not stuffed. It was definitely caused by the arc.

[rosie]

I'm no expert mate but on the vitara I've got a high amperage fuse box on the drivers side of the engine bay. It doesn't have anything written on it but I found it after I lost power when i ripped a cable off under the dash and it earthed out.

HTH

[chimpboy]

Fusible links can be a bit hard to spot. SOmeone familiar with Sierras should be able to tell you exactly where to find them, but I'd be looking around the firewall or the side of the engine bay.

Maybe in the fusebox in the footwell (I think there's one there in Sierras) but not as likely as the engine bay.

[v840]

All good. I finally found the fusible link ..............


















.....................It was right next to the positive terminal

[rosie]

Just out of curiosity, was it in a fuse box with big, chunky fuses. I was just wondering if i had another fuse to know about.

[v840]

nup. It was literally an inch or so from the positive terminal. It was hiding behind a cable connector. I dont know if this how they are all wired up however as mine has had an engine conversion. I dont even know if they definitely do have them from the factory.
Sorry I couldnt be more help.