I posted this to the av forum about a week ago but it doesn't seem very active over there

recently put a sub and amp in my 2013 gs (non ML stereo). When I was done and connected the battery the fuse on the wire blew. I double checked everything and found a couple possible causes but want to make sure I got everything right before wasting any more fuses.

I used a kicker kisloc loc that doesn't have a turn on wire, just speakers and ground. I tapped the small white wire on the other harness and have since found it is only 5v and I'm wondering if it might be constant power, possibly making the amp turn on when I connect the battery. I'm planning on finding a 12v known ignition source. I counted from the back of the harness instead of the front when tapping the speaker wires but don't think that would have caused the problem.

I've done several installs over the years with no problems but those have all been with aftermarket head units so I don't have any experience using an loc.

 

You shouldn't have to guess. It's either constant power or it's not. You should always verify voltage behavior before blindly tapping stuff. You have a multimeter I presume?

What rating is fuse that blew? Is it part of some amp wiring kit? What rating is the amp you installed? The fact it might "be constant on" versus come on later doesn't make sense. How would it not blow when you actually start listening to music and power demand increases.

Did you check to make sure your power wire going to the battery isn't shorted to ground? Did you disconnect the power wire from the amp to make sure it's not having continuity to ground? Then when you connect the power wire to the amp, the continuity to ground shouldn't be going low.

 

I was using 60 amp fuses with a fuse holder I bought separately. Wiring is 6 ga ofc. The amp is a 3k rms sundown but I don't plan on using anywhere near that much power. I checked the power wire and it's not shorted. I do have a 1/0 amp kit I can use if needed but used the smaller wire for ease of installation. As to verifying the power sigal I should have. I am getting ground at the amp +.

 

Would you be able to provide a model for your sundown amp? I'm assuming you have the below amp that's listed from their website. Unfortunately even if you don't plan on using that much power. It's recommend running the 1/0 w/ 250amp fuse as stated.

https://sundownaudio.com/collections...ss-d-amplifier

 

To verify, on your last sentence, did you mean that you get ground at the amp - ? If you get ground at amp +, then that's likely be a short somewhere.

To verify, you did the following checks?
With amp disconnected:
Continuity mode, power wire to ground - no continuity
Continuity mode, negative to ground - continuity

With amp connected:
Continuity mode, power wire to ground - no continuity
Continuity mode, negative wire to ground - continuity

I've never played with "large" amps like that, but is there a possibility that a 3kW amp would have a large inrush current from its internal caps that might be popping the 60A fuse?
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Sia2500.1
At this point I intend to use 1/0 and I have a 250amp fuse. Maybe I'm not thinking about it the right way but if there's nothing else wrong the fuse shouldn't blow regardless of amp rating and if the fuse on the 1/0 doesn't blow it could just keep heating up. That's why I haven't changed the wire yet.

 

I checked with a power probe so it just shows whether you have power or ground

First I checked with the wires connected to the amp. (Obviously not connected to the battery) And got ground at both terminals

Removed the power wire from the amp and it didn't have power or ground but the+ terminal on the amp had ground. Based on that I don't think the wire is shorted. I'm really hoping the amp isn't messed up. It was good in my last car.

I'm planning to replace the wire with 1/0 and a 250a fuse. I had been thinking it was a good idea to figure this out first but you may be right.

 

Looks like the amp is rated for 250a fuse. Would not use anything lower. Sounds like you found your issue.

 

I have an Alpine mono running the 10" sub and a 10 channel DSP taking signals from the stock ML. I pulled a 2AWG cable directly from the battery upfront to the back to a disti block. Remote + tapped from the stock ML. So far no issue.