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Remote turn-on/off for sub/amp

New 01/22/2005

Guys, the last few days I've been doin' some catch up, tryin' to upgrade the sound system on the '99. After installing a sub, amp and the necessary hardware, I can't seem to find a suitable place for the "remote sensing turn-on/turn-off". The '99 of course doesn't have an electric antenna so, where can I wire into that will allow amp turn-on/turn-off with the radio?? I've found most of the answers I needed on the website but, this one is stumping me. The hotwire I found from the harness in back (red w/yellow stripe) allows power to the amp but, won't turn it on/off with the radio. Same one Nimz's used for his power-on tap, I believe. Any help would be greatly appreciated.


Radio Fuse is a good spot.

Ryan Dudek

Can wire it to a fuse, but the right way to do it is wire it to the
accessory wire that goes to the stereo. Is the stereo aftermarket? If
it isn't aftermarket you could still do it that way, but it will require
some splicing into.


Use the wire that normally works the power antenna. It is in the left side of the trunk even though you don't have a power antenna installed. I believe it is black/pink.
Richard Wills

If I remember correctly that won't work since the power antenna wire only puts out 5 volts and the amp will need 12 volts to trigger. I can't remember what other people have done but I do know that DEI makes a unit that will detect signal on the input wires to the amp and create the +12 volts needed to turn the amp on. Some amps even have that feature built-in I believe.

Richard, I'm using a Lightning Bolt mono-block for sub power and it does have power sensing built in. I remember a "pink/black" wire in the loom. It should be plenty for the power sensing if it carries "trigger voltage" only. My main power comes from the power tap on the "Mega Fuse" block. One question, though.....where did you ground your amp? They tell you to keep the grounding cable the same gauge as your power cable and as short as possible. I grounded to the hard point for the rear seatback mounting plate. I may need to find another point as it's painted and not ideal for my installation. The grounding cable I have is 3 feet long so it'll have to be close.
My installation is nearly identical to the one described on the website under "Installing a subwoofer". Amp is mounted on the right fold down seatback and wiring is routed similarly I'm just having trouble finding a "trigger" for the remote turn-on and a good grounding point.

If that is the case and the amp wont activate with only +5, Radio $hack
sells reed relays that are 5 Volt coils, and then you could use the 5
Volts to close the relay to provide switched 12 (right off of your
main hot supply) to the amp's remote turn on input.

Of course the same thing could be done with a single transistor.....

All of this is assuming that it is only +5 for the power antenna, I'm
skeptical but have no experience in that area.


Well, I've been stumped before but, this was way too weird. After all the suggestions, wiring help, stickin' my tongue out and holdin' my jaw just right, I finally got it finished. It's workin' great, as a matter of fact. Richard you are indeed right.....the Black/Pink wire is the one to tap for remote turn-on power. On an amp with remote sensing, it will read the voltage spike (even 5 or so volts) and turn itself on. Actually it's on all the time, as long as the ignition is on.....it just activates the output transformers.
But, the thing that confused, confounded and befuddled me was the new amp wasn't the problem, all along. It was the factory radio.....Evidently it read a voltage tap, ground loop or something amiss because it completely turned it's output OFF. In other words, all this time I spent thinking I had to go somewhere else for a remote tap was wrong. The amp was on the whole time. There was no output from the radio for the new amp to read. I only found this by accidentally turning up the gain on the amp and just like that......low end feedback. I thought the woofer was gonna come outta the frame................The amp was on.
To ease the installation, I had decided to use high (speaker level) inputs. Most factory systems these days have decent specs and power and the SHO is no different. Basically 20 watts a channel x 4. But, the factory doesn't wire in RCA outputs. So, using speaker level inputs seemed logical.............Wrong.......................uhhh,
...............HOW 'BOUT ........NO!
After struggling with this thing for 6 hours today and a couple last night, I finally went to Best Buy where an installer was kind enough to take a look at it for me. Couldn't really say anything looked wrong. But, (crux of the biscuit) he told me they use line converters (speaker level to RCA's) for amp inputs on all their installations that keep the factory radio. After thinking a bit, I thought it might make sense. So, I purchased one, took it home, 30 minutes later.........music......and bass coming out of my sub!!...Sweeeeeet!
Many thanks to all those that tried to help.....
Rex in Ft. Worth




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