5-Channel amp wont fully start up on ignition

Hey guys,
I'm usually pretty confident with audio wiring, but this one is stumping me.

This is actually on my 1997 4Runner, which is newer to me. I recently picked it up with some sketchy audio installed by previous owner(s)...not the Taco... but TW is the greatest resource so here I am!

I just finished installing the following products:

1. Kenwood DPX500BT (inherited with the car)
2. Crutchfield 4awg Wire Kit
3. Boss PV3700 5-channel Amp (inherited with the car)
4. Crutchfield 14awg speaker wire
5. JBL Club 622 speakers (front doors)
6. JBL Club 522F speakers (rear doors)

Prior to install, the audio in the car worked, however it was distorted and low sound out of one speaker, the driver door. I inspected some of the wiring, and it was a mix of patch work jobs.
Originally, what looked to be close to 20yr old wires that took the high level output of a once OEM stereo and sent it to a 20yr old alpine amp (i found it floating around in the rear truck) and then back through the OEM speaker wiring to some blown out and 20yr old rockford fosgate door speakers. The amp was wired somewhat properly, as power was run from the battery with a fuse block, ground was short but wood screwed into the body of the floor pan, and the remote turn on wire was run to an orange wire stemming from the factory stereo wires, on the harness side (not the stereo side).
The inherited Boss PV3700 seemed to be patched in sometime later as the alpine was broken physically. I could see where some of the wire connections and speakers were the cause of the lack of sound and quality.

=== Point being, although old and outdated and sketchily done, the sound system components all worked together ===

I decided to start from practically scratch, and replace everything but the PV3700 and Kenwood as they seemed to work fine.

• I ran the amp power cable from the battery and attached the fuse properly within 10" of the battery, through the dash just above the accelerator pedal, and through the center console / shifter area to the Boss amp which will be placed under the driver seat.
• The ground cable is about 3' and runs to a ground bolt that's located behind the driver kick panel, near the dead pedal.
• Amp remote turn on was run from that same orange wire behind the dash, and followed the positive cable through the center console area, about 4' long.
• Speaker wires were run through the OEM rubber door sheaths, and along the respective driver and passenger door sills, crossing over to the passenger side behind the rear seats. This should keep them out of any interference from the main power wires to the amp for minimal distortion.
• Speakers bolted right up to the OEM mounts, with some adapters provided by Crutchfield for free!

Sorry this is getting long, but please bear with me.

I hooked everything up, and went to test the system, and low and behold the Boss amp was not turning on.
I unfortunately lost my volt meter, but was able to test the remote turn on by jumping it to the battery directly with my spare wire, and it started to power up for a second, but then shut off.

I then attempted to isolate a pinched speaker wire causing the amp to go into protect mode, and disconnected all the speaker terminals.
Same thing... It will attempt to power up and then immediately shut down...

I double checked both the power and ground connections... positive power is good, tight, and not pinched.
Ground should be good, but I am struggling to get a solid crimp on the ring terminal on the amp side.
No fuses on the amp, or power wire is blowing.

Attempting to see if the amp was in protect mode, I watched the power and protect lights.
The amp is not even staying powered long enough to keep the protect light lit?!?!


TY if you've made it this far...

My assumption is that the Boss amplifier is good and working, as it was before with the sketchy old wire setup.

As of now, I am stumped as to why the amp is not starting up fully, and almost "softly" shutting down, like it has not enough power. I don't believe it is going into protect mode, as its not a hard shut off, and the protect light is not lit.

My main questions are:

1. What's a good alternative remote turn on power source?
2. My 4amg wire kit should be well within the means of powering this 3700 watt amp, as I won't be even close to using its full power with my entry level speakers, am I correct in this thinking?... Could the awg somehow be too thick, causing impedance and not enough power to reach and turn on the amp?
3. Any other suggestions on how to trace this issue?

I will get a new volt meter and get some actual readings on what's getting to the amp from the positive power, and remote turn on wire once I decide on a new location...

Ty all in advance.

 

Check the specs for the head unit. Amp remote is usually blue or blue/white. Orange is usually illumination.

 

Subbed for a resolution.

If I had to guess the amp is toast or there's a connection issue. "Ground should be good, but I am struggling to get a solid crimp on the ring terminal on the amp side."

Do you have another amp you can try?

 

Bout to say like above, orange is usually the illumination circuit and solid blue is remote out. Easiest thing without tearing the dash apart is just run a wire off an ignition only 12v+ from the OEM fuse box as your remote.

You can run a remote wire directly to the battery and see if the amp turns on at least to rule out the amp quickly.

 

I am questioning that ground too...
Unfortunately I do not have another amp.

 

I did try running some wire direct to battery.

I did the same thing..

I plan on getting the remote location sorted out. Hopefully this stereo has got an output for it. That would make it easy.

Second is getting a good ground. Ah the struggles of proper grounding I deal with problems like these all day at work with motorcycles! Electrical is not my forte, but I know enough to think I can do it correctly the first time... and usually get it right.

 

I'm about 20yrs out of date but I'll agree with this guy as blue was typically remote.

 

Blue or blue/white-stripe is a universal standard on aftermarket gear for remote amp output, however, he indicates the wire was spliced on the vehicle side of the harness. Meaning one needs to reference vehicle wiring diagrams for color coding, or reference factory harness pin location functions(I've had multiple vehicles that never match official factory wire color diagrams).

But it's a very poor way to do remote turn on, especially with an aftermarket radio.

This is one of those times where all the previous owners mistakes possibly made up for each other, and you likely ended up 'ruining' it by trying to do it right!

If the ground connection is suspect, I would investigate that first. A volt meter here won't help, as the cable likely has a good ground, but the terminal could be preventing the amp from using it. I've made that mistake before, it's sometimes really easy to strip out the terminal, especially one someone else boogered up, and you'll need to drill and tap it out to one screw size larger.

Right now, with only trying to get it to turn on, you could easily run speaker wire straight from a battery to the amp to test and verify. It's not good for any power output level, but enough to test for functionality.

But it's also entirely possible that the amp is bad now as well for any number of reasons.

My first step would be to take a deep breath, remove the amp from the vehicle, and using a battery on a work bench and short test wires, set it up for installation. If it still displays the same symptoms, it's bad.

If it suddenly powers up, track down a 3.5mm to rca cable to plug your phone/iPod/computer into it for a source, and hook up a random speaker on the output. Then you can verify each output of the amp is working correctly.

Then, if all that checks out, put it back in, and work backwards away from the now known-good amp to verify power, ground, and signal connections.

 

TY sir.

I shall try and get these things tested on the amp on the bench & addressed on the vehicle side of things.

 

didn’t quite have time to pull the battery out and test the amp on my workbench, but repaired the ground wire, and did some testing with my multimeter.

Battery with the car off is 12.5 V
Battery with the engine running is a healthy 14.5


at the amp, power and ground terminals show 12.5 V


the remote turn on wire shows .05 V


However, when I turn the ignition on, engine running or not, The power wire drops to about 2.65 V and the remote turn on wired drops to about 1.85 V.
The owners manual for the boss PV 3700 states on the troubleshooting page that it needs to see 12 V and 3 V respectively for those two terminals.


This is still without any of the RCA or speaker. Wires connected.

 

you've got a poor connection somewhere before the amp on your power wire. check your fuse. both the connections at it, as well as the fuse itself.

right now, the wire is a bit like a coffee stirrer straw. enough to let some voltage trickle through when there's no real demand, but if the amp turns on, it's like a person trying to run a marathon while still breathing through the same tiny straw, which is why you're seeing the voltage dip when the amp attempts to turn on.

i would suggest using a 12v incandescent light bulb-- i suspect if you connect it to the amp power/ground with some test leads as-is, it's going to show similar symptoms(dimly lighting, low voltage) of a bad connection somewhere.

just don't test the remote wire with the same incandescent bulb-- to many draw more than most radio's can supply.

 

I ended up tracking it down to a bad ground ! (Of course)

Tried connecting the multimeter to the amp ground and then a other spot on the body, without the ground strap connected… amp turned on…

The location I was using on the car body side was good, however I had sandwiched the amp ground strap over an existing ring terminal, assuming it would ground ok.

I guess it was simply getting enough connection from the bolt alone to show 12v with the amp off, but when a load was applied it couldn't handle it.

I placed the amp ring terminal below the other one, scuffed everything up, and everything worked as it should !

 

In other worlds though, one of my main accessory power wires on my Tacoma found its own (short to) ground when a rock slung up and drug the frame while cruising through a whoop section in Lucerne at about 45mph…

Caused the whole truck electronics to flicker once, twice, and shut off completely… while still going about 40 through some big stuff… not a pleasant feeling to say the least battery light and CEL were on.

I found the culprit wire after jumping out of the truck and smelling some burning.. a solid 12awg lead from the battery terminal under hood had shorted just underneath the driver seat frame rail. There was absolutely no wire sheathing left on that stretch jumped back in and hit the battery kill I have on the center console and maybe saved the truck from getting to a worse state.



Cut out the shorted wire and flipped the battery kill back on — truck started right up like nothing happened. Gotta love em.
I’m going to check some of the other wiring that was near this one for heat damage this week.

 

And that's exactly why proper fusing is so important!

Glad you got it figured out!

 

100%!
I am usually pretty good about that, marking sure everything is safe in terms of fuses, wire awg, and their limits…
This one was done probably 7 years ago when I knew way less of what I was doing I’d forgotten about it until now !