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Discussion Starter #1
Hi All,

I have 2001.5 GLS which I recently bought but can't for the life of me figure out why the sound on the radio doesn't work. I've searched a lot and even bought a new monsoon amp but there still isn't any sound. I've even used a multimeter to check for power on the green plug that connects to the amp but don't see anything. There is power coming from the headunit for each channel on the white plug to the amp though. The headunit also powers the cd player just fine as well.

Does anyone know what else I can do or anything I should check? The headunit powers up normally, it's just that even though I crank the volume to max, there isn't any sound coming out of the speakers. I've also tried pulling fuse 37 to reset the system without any luck.

I attached a picture of the harness on the headunit. Are there supposed to be wires in that yellow section which power the amp?

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The monsoon amplifier gets audio signal from the wires coming out of the brown connector. The pins in the yellow connector are unused with this system. The amplifier is not powered by the head unit. The amp has its own 30A fuse under the dash. I'm not sure if it's located in the fuse panel with all the other fuses or down under the 13-fold relay panel. The amp always has power available and turns itself on and off based on the presence of audio signal coming from the head unit. There are two connectors plugged into the amp. One has about 8 wires and is the audio signal coming in from the head unit. The other has more then 18 wires and is the amplified output going to the speakers. That connector also has power and ground in it. Pins 18, 21 & 23 should be powered by a red/brown wire. Pins 19, 20 & 22 should be frame ground through a brown wire.

Check for power at the Monsoon amp. If none found, find the fuse and test it.
 

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Fuse 37 powers the radio (head unit) but not the Monsoon amp (in the trunk).

The Monsoon amp has a separate 30A fuse, designated S260 in the schematics, but it's location isn't specified. You must have 12VDC between the red/brown (+) and brown (-) wires that plug in to the Monsoon amp for it to work. If you don't, that fuse would be the first thing to check. This power is unswitched, always hot. You can measure voltage at the plug with it unplugged from the amp.

The schematics (Bentley schematic 68/3) say power comes from threaded connection 30 on the relay plate (behind the headlight switch). Since terminal 30 is unswitched, unfused, battery voltage, I'd bet the fuse isn't far from the relay plate, probably inline in the radio harness. It's a 4[SUP]2[/SUP]mm (10AWG) red wire to the fuse, then 4[SUP]2[/SUP]mm red/brown after the fuse.

Pull off the cover below the dash and have a look--trace any large red wires that originate at terminal 30--there won't be many. I bet you'll find a 30 amp fuse before long. The red/brown wire color after the fuse will be a good clue that you've found the right one.

Let us know!
 

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Discussion Starter #5
Just got back from the car with all the plugs plugged in to the amp. On the 22 and 23 wire the multimeter only shows .03 volts coming in. Does this mean I have to find that relay?
 

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Not a relay, a fuse... but yes, it's very likely blown. BTW, the voltage should be there (on the plug, not the amp) whether it's plugged in or not, because the power comes from the wires (from the fuse behind the dash). The fuse is probably identical to the ones in the main fuse box, but (probably) in an inline fuse holder.

There's an outside chance that the ground is defective, but that's very unlikely. You could easily check it with an ohmmeter; unplug the connector from the amp and measure between each brown wire (in turn) and the outside ring of the trunk power ("lighter") connector. And, if the ground (to the amp) is defective, you would measure 12 volts DC between the trunk power connector ring and the red/brown wires.

Again, 99% chance the fuse is blown. When you find it, test it with an ohmmeter, not just visually--they can be blown and still look OK.
 

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Discussion Starter #9
I want to thank everyone for helping me solve my issue. I was pulling my hair out trying to figure this out. It was the 30A fuse hiding under the relay. I swapped the power windows thermal fuse into the Monsoon amp slot and sound began coming out of the speakers again. Since I could never find a picture on the forums, I took a few so anyone in the future can see where it is located. The 30A fuse that was connected to the Monsoon amp rattles when you shake it. This thing is $34 MSRP. Part number 443 937 105A.

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I want to thank everyone for helping me solve my issue. I was pulling my hair out trying to figure this out. It was the 30A fuse hiding under the relay. I swapped the power windows thermal fuse into the Monsoon amp slot and sound began coming out of the speakers again. Since I could never find a picture on the forums, I took a few so anyone in the future can see where it is located. The 30A fuse that was connected to the Monsoon amp rattles when you shake it. This thing is $34 MSRP. Part number 443 937 105A.

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Thank you so much for all this information. My amp and windows were not working and this was the culprit. Changed both of those fuses/relays and that fixed it!
 

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Reviving an old thread here...

I have a 2003 golf tdi with what appears to be the same issue: no 12V going to the Monsoon amplifier in the back. On other forums I saw folks powering about fuses 37 and 42; checked those and they're fine. I found only one obvious fuse that looks exactly like pn 443 937 105A (not in the fuse box, but down under the steering column).

Wondering if anyone else with my vehicle has discovered the same issue. Clutch pedal makes it extremely hard to fish around down there. I've been removing relays searching and still empty handed.
 
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