Ecm fuse #5 keeps blowing

[lil-bit]

2010 by Camaro 70k miles.
No mods completely stock car.


A while back we had the AC go out. We took it to the dealer and the came back saying it was a bad fuse box under the hood. Which is like 260 dollars only problem is the part is back ordered everywhere. That's fine we'll now. The car doesn't start. We changed the battery alternator and the starter. Keeps giving us a U0100 code Wich is no power to ecm. When I pull the fuse its blown so I replaced it with another 15 amo fuse. It starts then when I turn off and try to repeat the fuse is blown again. I tried going through the wiring I don't see any physical damage. Could it by the actual fuse box causing this. Since we can't even get the part it's hard to just sit and wait in hopes that it's that.

Any suggestions would be greatly appreciated. Thank you

[Gordo-D]

Makes you wonder why they are on back order.

When I have had vehicles in for jobs with consistent blown fuses [old Nissan Micra's for one] its usually water getting inside the fuse box, not sure how that can happen on these, so that leaves poor build quality?

[lil-bit]

I tried to see if there was a short in that particular fuse location with my ohm meter but I see no short wonder if it's something else triggering it during crank ...

[JerTM]

Originally Posted by Gordo-D

Makes you wonder why they are on back order.

When I have had vehicles in for jobs with consistent blown fuses [old Nissan Micra's for one] its usually water getting inside the fuse box, not sure how that can happen on these, so that leaves poor build quality?

Probably age. They slow production of oddball parts as the vehicle gets older so when they discontinue them they aren't stuck with a bunch of inventory.

[Low Saturn]

Check the engine wiring harness that run along the upper front of the engine then turns down on the front passenger side corner of the engine above the exhaust manifold. The wire harness clamps are made of thin sheet metal and act as razor blades with engine vibration. They eventually cut through the wire loom then the wires. Mine cut through several wires, then allowed the harness to slide down onto the exhaust manual. Also melting a few wires. In my case, I kept getting engine codes for cam, crank sensors and rough idle. Problems went away after I repaired the wiring, replaced the clamps and rerouted the harness.

[HyperV117]

Originally Posted by Low Saturn

Check the engine wiring harness that run along the upper front of the engine then turns down on the front passenger side corner of the engine above the exhaust manifold. The wire harness clamps are made of thin sheet metal and act as razor blades with engine vibration. They eventually cut through the wire loom then the wires. Mine cut through several wires, then allowed the harness to slide down onto the exhaust manual. Also melting a few wires. In my case, I kept getting engine codes for cam, crank sensors and rough idle. Problems went away after I repaired the wiring, replaced the clamps and rerouted the harness.

Shit that's good to know. Going to check mine later today.

[lil-bit]

Okay thank you. I'll check the wiring harness when I get home. This morning I also did take the fuse from the starter out. Then I tried to crank the car obviously it wasn't going to start without the fuse for the starter but it didn't blow that fuse the ECM fuse anymore. I don't know if that's an indication of anything or if that's just something else

[christianchevell]

Never heard this one...…. would wonder that there is undoubtedly a note online with a tech explanation you can find looking for recalls at NHTSA website...… but most likely not there..... a short is the explanation...… figure it from there and trace the wires, don't believe everything your fed..... and surely there is a parts car with the fuse box...….somewhere. And most clamps just like the covering for the harness are plastic and have barbed push connectors to the frame. But in some hotter locations......or varied places yes they are metal, but even then they are coated also.

[lil-bit]

Yeah I followed all the wiring I could see. All plastic straps but nothing looks damaged. So weird. I have an ohm meter but not sure how to even trouble shoot the wiring from the fuse box. Like what should they show. It doesn't blow unless the car tries to turn over. So if the starter doesn't turn the motor it's fine once the starter kicks on bam the fuse goes. It'll even start and run but once you turn it off the fuse is gone

[Low Saturn]

Originally Posted by christianchevell

Never heard this one...…. would wonder that there is undoubtedly a note online with a tech explanation you can find looking for recalls at NHTSA website...… but most likely not there..... a short is the explanation...… figure it from there and trace the wires, don't believe everything your fed..... and surely there is a parts car with the fuse box...….somewhere. And most clamps just like the covering for the harness are plastic and have barbed push connectors to the frame. But in some hotter locations......or varied places yes they are metal, but even then they are coated also.

The two harness clamps in that position are definitely not coated metal clamps on my Camaro . They are bare sheet metal clamps with sharp edges. I can get a couple pictures of mine when I get home. My Camaro is a 2011, so the clamps may of changed in later years, but I can guarantee that mine are razor sharp clamps that cut through the loom and wiring. There is also a TBS concerning this issue.

[lil-bit]

I guess the question... A short on the light bulb wouldn't blow a ecm fuse I wouldn't think. Or short on a non important fuse mess with the ECM. What component or components is the ECM dependant on that would most likely cause the ECM fuse to blow.

[irwires]

Need to check for a low voltage condition or a bad ground connection. As voltage goes down amperage goes up so the ECM is going to draw more amps. Grounding connections are very critical in these vehicles. A high resistance ground connection will cause higher amperage's. Temporarily try a 20 amp fuse. If it doesn't blow then most likely it's a low voltage condition. Go back to the 15 amp fuse and start searching and re-doing connections from the battery forward. Also use a name brand fuse.

[lil-bit]

Originally Posted by irwires

Need to check for a low voltage condition or a bad ground connection. As voltage goes down amperage goes up so the ECM is going to draw more amps. Grounding connections are very critical in these vehicles. A high resistance ground connection will cause higher amperage's. Temporarily try a 20 amp fuse. If it doesn't blow then most likely it's a low voltage condition. Go back to the 15 amp fuse and start searching and re-doing connections from the battery forward. Also use a name brand fuse.

10-4 will try this tonight. Let ya know

[lil-bit]

Originally Posted by irwires

Need to check for a low voltage condition or a bad ground connection. As voltage goes down amperage goes up so the ECM is going to draw more amps. Grounding connections are very critical in these vehicles. A high resistance ground connection will cause higher amperage's. Temporarily try a 20 amp fuse. If it doesn't blow then most likely it's a low voltage condition. Go back to the 15 amp fuse and start searching and re-doing connections from the battery forward. Also use a name brand fuse.

So it started about 5 or 6 times then it almost acted like a dying starter or battery so I charged the battery over night and then as soon as I turned the key this morning it blew the fuse. And the starter was really weak sounding also. It didn't want to crank.