Subs stopped working, amp getting power?

[marky227]

Hey guys, hoping to get some input or thoughts on this... I have a bmw with a custom mounted 12" subwoofer in the trunk.. Ive had problems in the past with the sub turning off after driving for a while.. so i assumed this was the amp going into protection mode.. I bought a fan i was going to mount on the amp finally, but the sub doesnt work at all now.. The amp is however getting power, im almost positive its not the rca's at the head unit cuz i went in and double checked those before i realised it was the amp turning off for protection mode...checked my main grounds and all wires at the amp..everythings good.. Could the amp have overheated but still is turning on? Is there any fuses inside the amp i could check? the sub is mounted on the top part inside the trunk, so its somewhat an ordeal to get the sub box down. And i dont see why a connection there would go bad, unless i blew the sub which doesnt seem likely.... any help is appreciated alot!

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[americannight 10+ year member]

Try turning off the stereo for about 20-30 seconds and then turning it back on. If it works after that then it's probably a thermal (heat) issue. There are thermal fuses in most amps which will trigger if they get too hot. But depending on the amp, you may still see lights on when that fuse is tripped. If it's a thermal issue, try mounting your amp where it gets better air flow or use a fan.

 

[marky227]

Try turning off the stereo for about 20-30 seconds and then turning it back on. If it works after that then it's probably a thermal (heat) issue. There are thermal fuses in most amps which will trigger if they get too hot. But depending on the amp, you may still see lights on when that fuse is tripped. If it's a thermal issue, try mounting your amp where it gets better air flow or use a fan.

Well it hasnt worked in a few days...i mean its sat overnight with everything off for a cpl days now.. i had the negative terminal off my battery for a while and everything and it just wont produce any sound.. I was looking for a reset button on the amp incase something like what you said had happened (tripped fuse)... but couldnt find one...

 

[americannight 10+ year member]

Is there any fuse or circuit breaker in line with the power lead going to the amplifier?

 

[marky227]

Is there any fuse or circuit breaker in line with the power lead going to the amplifier?

theres a big one going from the amp + to the + battery terminal.. but it looks fine.. its in a clear tube and i can see it looks ok

 

[americannight 10+ year member]

theres a big one going from the amp + to the + battery terminal.. but it looks fine.. its in a clear tube and i can see it looks ok

To be thorough, you might test the fuse with a multimeter to make sure it has continuity. It's rare but fuses can look fine and be blown. After reading through this whole thread I'm thinking your amp is blown but check all the simple stuff first including the fuse. Hook another speaker up to the amp to see if you get sound out of it. Run an ipod or mp3 player into the RCA inputs on the amp to rule out that it's the head unit. Check all these simple things first and if nothing pans out, you probably need a new amp.

 

[marky227]

To be thorough, you might test the fuse with a multimeter to make sure it has continuity. It's rare but fuses can look fine and be blown. After reading through this whole thread I'm thinking your amp is blown but check all the simple stuff first including the fuse. Hook another speaker up to the amp to see if you get sound out of it. Run an ipod or mp3 player into the RCA inputs on the amp to rule out that it's the head unit. Check all these simple things first and if nothing pans out, you probably need a new amp.

thanks for the replies!! I got the sub/box out and a multimeter.. But last night when i was checking stuff again.. I pushed up on the sub cone.. and it started working.. briefly. So i thought maybe the connection was bad so i took it out and reclamped the wires to the sub and tried again.. same thing.. now it will only push bass if i hold the sub in.. So it must be blown right? I dont see how it would have blown all a sudden i didnt have it up crazy loud and thought maybe the connection was bad and thats why it cut in and out in the past.. any way to test the sub itself to be sure its blown?

 

---------- Post added at 02:09 PM ---------- Previous post was at 02:08 PM ----------

 

To be thorough, you might test the fuse with a multimeter to make sure it has continuity. It's rare but fuses can look fine and be blown. After reading through this whole thread I'm thinking your amp is blown but check all the simple stuff first including the fuse. Hook another speaker up to the amp to see if you get sound out of it. Run an ipod or mp3 player into the RCA inputs on the amp to rule out that it's the head unit. Check all these simple things first and if nothing pans out, you probably need a new amp.

thanks for the replies!! I got the sub/box out and a multimeter.. But last night when i was checking stuff again.. I pushed up on the sub cone.. and it started working.. briefly. So i thought maybe the connection was bad so i took it out and reclamped the wires to the sub and tried again.. same thing.. now it will only push bass if i hold the sub in.. So it must be blown right? I dont see how it would have blown all a sudden i didnt have it up crazy loud and thought maybe the connection was bad and thats why it cut in and out in the past.. any way to test the sub itself to be sure its blown?

 

[marky227]

weird... the sub wont read any ohms unless i push it in..and then its all over the place like 2 to 7 to 3 to 9 to 4.. must be blown right?

 

[gumby688 10+ year member]

yep