Help! Monsoon Amp Won't Turn Off
 

So I helped my dad install a new head unit into his 01 SS convertible on Saturday.

This is the third head unit install I've done, and the second to interface with a "factory premium" amp. The previous two cars had Zero issues.

The problem is that the Monsoon amp doesn't shut off when the car turns off.
With the key out of the ignition, doors closed and locked, you can still hear really faint static through the door speakers.

I was afraid it was a problem with my harness, so I disconnected everything I had installed into the car. This part is important- at this point the car is technically 100% back to stock, and there is nothing new connected to the car. The amp should not be receiving the "power on" signal, and thus should be off.

But...it STILL stayed on. I tried moving the Amp Turn-On wire to from "Amp Turn On" location on the adapter over to the "12V Accessory" wire just for kicks, and still no luck. Same shit.

I also added an extra ground wire from the harness directly to a metal bracing (which I sanded to clean) just in case.

Another point: at one point after hooking everything back up, the amp apparently had turned off but now would not turn ON. Turning the car off and on again seemed to turn the amp back on.

Any ideas on what this could be, and how to fix it?

For the record, I'm not interested in bypassing the factory amp.

Its a huge problem because the running amp kills the battery pretty quickly.

The Monsoon amp does not have or use a remote turn-on wire so I'm not sure what you mean when you describe moving the turn-on wire. The factory configuration has the amp powered by a constant (battery) power source and turning on/off based on signal sensing on the input side.

If it is not turning off when no signal is present then the amp itself is probably faulty although I haven't heard of that particular problem. Are there any other symptoms such as balance/fader issues or some of the speakers not working?

The amps I'm used to have two types of positive wire- the big heavy power cable to the battery, and a smaller "signal wire" that tells the amp to turn on whenever when a 12V voltage is present. In my own car, I have this wire spliced into the 12V accessory power circuit. So when the car turns on, so do the amps. While my own headunit has a cable on its harness for this purpose, I prefer to have it on a switch.

I have no idea how the Monsoon amp is connected, but I assumed it was more or less the same way. The Camaro-specific adaptor harness -- the one that mates to the headunit's harness -- has a blue cable which was labeled "Amp Turn-on" on the packaging. I mated this to the blue/white "amp turn-on wire" on the headunit harness.

In theory all its really doing is presenting a voltage to the amp letting it know to switch itself on when the headunit turns on.

After that didn't work, I switched it to the 12V accessory circuit, which- again- will just be presenting a voltage to the amp sensor, only this time the amps will be on whenever the car's ignition is on, regardless of the radio's status.

So are we saying the same thing here, or does it use some different sort of signal-sensing?

Thank you, I am well aware of what a remote turn-on wire is and what it is designed to do. Unlike the majority of aftermarket amps, the Monsoon system does not have such a wire. The amp turns on and off based on whether it senses audio signal from the head unit.

The remote turn-on wire (blue/white) in the adapter harness is there because the harness is a somewhat universal design and the wire is needed by most aftermarket amplifiers. It is of no use in a Monsoon system.

If anything you could just hook up the power to the amp and the signal wire to a relay and have the signal wire tell the relay to provide power to the amp... just a thought.

I assumed as much, but it helps to know what I know so we're on the same page here. ;)

That's kinda weird. What does that blue cable connect to, then? It wasn't just on the adaptor harness; it looked like it was on the car harness too.

FYI, the blue wire I'm talking about is just solid blue. The blue/white wire is only on the headunit harness.

(Just to clarify on what I mean, it's Headunit Harness --> Adaptor Harness --> Car Harness)

The solid blue wire is for power antenna. The blue/white wire is remote turn-on (unused in a Monsoon system). The complete list is in the Monsoon FAQ sticky at the top of this section.

Yes, if it turns out that the Monsoon amp is faulty in that it won't turn off when there is no audio signal present and that nothing else is wrong (i.e. no dead channels or balance/fader problems) then installing a relay in the main power feed for the amp and tripping it via the unused remote turn-on wire from the new head unit will fix the symptoms.

Cut the orange power wire someplace between the fuse panel and the S333 splice (about 9 inches from where the CD changer harness power splits out). If you make the cut further along in the harness, you'll have to deal with the two orange wires both carrying power to the amp. Connect terminal 30 to the cut end of the wire coming from the fuse panel (constant power). Connect relay terminal 87 to the cut end of the wire going to the amp at the back of the car. Connect terminal 86 to the blue/white wire from the head unit or harness adapter. Connect 85 to chassis ground. Now the amp will only be on when the head unit is on.

Thank you! I appreciate your help! :)

Now here's where my ignorance will show: I know how relays work, but I've never actually used one in a circuit before, and I'll need some advice on which to get.

Thinking out loud: I don't know the efficiency of the amp, so its safer to assume 50%. With a rough battery voltage of 13.8V that would give you a current draw of about 30A.

So I'm guessing what I need is an SPST automotive relay rated for 30A?

The most common automotive relay is a 30A SPDT usually called "Bosch-style" or "Tyco-style". The current draw of the amp is less than 25 amps (that's the factory fuse size) so the 30A relay is sufficient. They have five terminals labeled 30, 85, 86, 87 and 87A. 85 and 86 are the relay coil terminals, 30 is the power input, 87A is the normally closed terminal and 87 is the normally open terminal. These relays are available at all auto parts stores, Radio Shack and probably even Walmart. If you get a more expensive one, it normally will include an internal flyback diode which means you have to watch the polarity of the coil connections... 86 to 12V+ and 85 to ground. If the relay doesn't have a diode, you can connect the coil either way but it's still conventional to have 85 as the negative side.

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Cool! You have been tremendously helpful. Thank you.

Similar issues
 

I have an 02 Camaro convertible with the monsoon system. I installed all new speakers, subs, and HU. I have no sound from the door speakers. There is power going to the factory amp and I installed a relay (assuming it's in the correct spot) . If I hook the factory radio back up, the speakers come on.

Why would you install a relay? That is a band aid fix for a very specific problem where the amp wasn't recognizing the audio input to turn off... and frankly, I've never seen another example of that happening other than this thread. Since yours works with the factory head unit but not with the aftermarket one, the problem is most certainly not with the amp and the relay just introduces another point of failure. Remove the relay and put the amp wiring back to the way it was. Then if it still doesn't work, you can be certain that the problem is with the aftermarket head unit. Start looking into why it isn't sending signal for the front speakers. It could be something as simple as a setting (e.g. speaker output vs pre-amp (RCA) output) or a problem with the wiring of the wiring harness adapter, or it could be a faulty head unit.