Pre-Amp out wiring

[Bob543210]

I have an 01' LS Sport w/ the Alpine sport system (w/o the rear amp and speakers in the trunk deck and with the in-dash CD changer). However, the pre-amp wiring harness is in the trunk. I would like to install my Infinity Kappa amp and 12" JBL Power sub. Unfortunately, I am not getting a voltage reading on any of the wires in the trunk. From reading other posts, I gathered that the remote on is the red and yellow. I tested this terminal coming straight out of the receiver and got a reading of around 7 volts. Also, all the other pins gave off a voltage ranging from 1 to 7 volts. I was wondering if anyone could tell me if this line-out is disconnected somewhere in between (since amp and speakers were never installed on my model) or if any of you have encountered a similar problem. Also, any advice on any other wiring problems encountered would be helpful. Thanks.

[Quik_LS]

I have a '01 with the premium sound.
- Alpine SPS-570A 5"x7"/6"x8" 2-way in the doors
-Sony Xplod 1000w Amplifier/Subwoofers Package (XM-2165GTX amplifier / 2x XS-L1200B 12" subwoofer)
- Rockford 1 Farad Digital Capacitor
- 4guage wiring

Here's the wiring....

Stereo Wiring:

According to the FOMOCO wiring diagram for 2000-2002, the factory harness connectors are wired as follows:

The large 20-pin connector:
Position 5 and 6 = right rear (- white and + gray)
Position 12 and 13 = left rear (- whit/violet and + gray/white)
Position 7 and 8 = right front (- white/red and + gray/red)
Position 14 and 15 = left front (- white/black and + gray/black)

Constant power = position 9 (orange.black)
Switched hot in start = position 3 (gray/orange)
Switched hot in run or ACC = position 10 (yellow/green)
Ground = position 16 (black/green)

The 16-pin connector contains the connections to the steering wheel controls and various data bus signals. The cassette systems with external CD changer have a connector dedicated to the signal cable for the changer.

On audiophile systems, there is an 8-pin connector wired as follows:
position 1 = sub + line level signal (gray/red)
position 2 = sub - line level signal (white/red)
position 3 = shield for sub amp signal
position 4 = +12 remote power to sub amp (yellow/red)
position 5 = center channel - line level signal (gray)
position 6 = center channel + line level signal (white)
position 7 = shield for center channel signal
position 8 = +12 remote power to center channel amp (yellow)

The trunk connector (on the drivers side) is number C465 and the sub audio uses these pins:
1 = yellow/red: switched hot
3 = shield for low level audio signal
5 = red: constant power from battery junction box fuse F418 (20 amps)
7 = white/red: low level LEFT audio signal
8 = grey/red: low level RIGHT audio signal

[Bob543210]

Thanks Quik. I saw that wiring on an earlier post and it was very helpful. However, my problem now is that I am not getting any sort of signal(voltage) out of any of those wires leading into that trunk harness.

[Quik_LS]

Originally Posted by Bob543210

Thanks Quik. I saw that wiring on an earlier post and it was very helpful. However, my problem now is that I am not getting any sort of signal(voltage) out of any of those wires leading into that trunk harness.

Well.....

if the trunk connector:
1 = yellow/red: switched hot
5 = red: constant power from battery junction box fuse F418 (20 amps)

so if you get nothing on these it is probably not connected.

On the back of the head unit there is an 8-pin connector:
position 4 = +12 remote power to sub amp (yellow/red) which goes to the pin 1 mentioned above.

[el es]

Man now that is down to the wire. I have this one bookmarked.

[Mizery]

Hey, I have a similar setup to what you're trying to do. I've got an 01 LS without the subs in the back and have been trying to hook up my current amp and sub using the preamp connector in the trunk. Let me tell you, it is a bitch. However, maybe I can help you with what I've found. Yeah, the voltage levels are really small out of the signal lines. I measured up to like 50mV with the volume of my stereo all the way up - and that's way too loud to listen to music. I bought a gain booster from PAC audio called Turbo1, I believe. That helped a lot, increased the gain on the signal lines to a level my amp could use. I also had a friend help me, and we looked at the signals with an oscilloscope. Turns out that the signal lines have a DC offset of about 4 volts (Alpine messing with you so you can't connect an aftermarket system). This sets the AC audio signal at 4V above ground level. I'm not sure how amps will deal with this. Mine actually seems to work fairly well, the sub plays all the bass at a good level.

However, I have another problem. Since hooking this up, I have a lot of engine noise (or alternator whine) playing out of my sub now. Everyone says make sure the grounds are connected well or install a groundloop isolator. Well, my ground is connected to metal on my chassis (no paint there), and I even tried a groundloop isolator inline with my signal lines. The isolator doesn't do a thing. It is actually installed after the Turbo1 gain booster. Installing it before the booster doesn't let any signal through. We think it's because of the DC offset - the isolator transformers don't let anything through. My friend (we're both electrical engineers) thinks I'll have to tap right off the back of the stereo before any engine noise gets absorbed by the lines and rig up some kind of circuit to get rid of the DC offset. This way, the isolator can properly get rid of any engine noise before the Turbo1 boosts the gain on the noise as well as the signal. I'm not sure what kind of circuit this would have to be - I'll have to talk to him about it some more. Anyway, it's not terribly bad right now, I usually have the stereo up loud enough that I don't hear it, and it adds a little low-end growl to my engine, hehe. But, if you aren't attached to the stock head-unit, just replace that and use the preamps off the new one. My stock head-unit has 6 disc changer built in, so I'm not getting rid of that. Maybe you'll have some luck and not have any engine noise.

[Bob543210]

Thanks Mizery. I'm a Civil Engineer and always tried to sleep through Circuits class, so I don't know much about why and how this crap should work. However, I did, finally, get everything to work. I completely gave up on using any part of that harness. I wound up just splicing into the rear speaker wires behind the head unit and buying a line converter. I also grabbed a remote off of another part of the HU. I ran the wires right down the middle of the car (really easy). If I had known everything I know now, this whole process would have taken about an hour. I'm just glad everything finally soulds great!

[Mizery]

Splicing off the rear speakers worked for you? I tried that first, and couldn't get it to work right for me. I got a good volume for my subwoofer, but it sounded like crap - just really bad-sounding bass, not sure how to describe it. After my friend and I looked at some stuff with an audio test CD, we came to the conclusion that the stereo has a crossover to the door speakers that cuts out low frequencies. I can't remember what it was, but the door speakers wouldn't play below like 80Hz or so. We thought that high cutoff frequency wasn't letting quality bass through to the subwoofer amp. We also found a cutoff frequency of 60Hz for the connector in the trunk for the subwoofer (it won't play above that). I guess if it works for you, that's good. Did you come off both rear speakers? I tried just splicing off one speaker as I didn't want to tear up any more wires than I had to. Someone suggested the additional load of the sub amp may have thrown off the impedance the receiver was expecting to see - distorting the signal coming from the receiver. Anyway, glad to hear it works for you. I'll have to figure out some way to get rid of the engine noise in my setup.

[Bob543210]

Mizery,
Yeah, you’re right. I got everything installed and declared victory a bit prematurely. I got it installed the other night, and although it did not sound like it was getting real deep (did have plenty volume), I just figured I needed to do some simple tuning on my amp. I tried that to no avail and then read your email. I’ll try to find one of those gain boosters tonight and rework my wiring a bit. Did you ever find a cause/solution for your alternator whine? Hope I don’t have that same problem. Did you choose your name based on your stereo probs, b/c this is getting frustrating.

[Mizery]

I can't figure out where the alternator whine is coming from. Everyone says make sure everything is grounded well. I've check that, my amp is grounded to a bare spot of metal in the trunk. It seems to enter the system in the gain booster. There is no noise if I connect the amp directly to the wires in the trunk connector. Of course, the gain booster is going to increase the gain on everything, including any noise in the line. So, that may be why it shows up when the gain booster is connected. Anyway, I don't know what the problem is. I'm fairly slow to get things done, anyway, so you may not want to wait for me to come up with a solution, hehe. The easiest solution would be to just replace the receiver, but if you have the one with 6 disc changer built in, I don't think you'd want to get rid of that.

I've used this name online for a few years in gaming and stuff. But, this problem is making me pretty miserable.

[ponchonutty]

Let me state a few things. 1st, it has always seemed that I have had problems when adding a sub to a factory head. Mostly is the bass cut off. Most OEM stereos play plenty of bass but as you turn them up, they turn the bass down. This is so they can run cheaper amps and speakers and not worry about clipping. The other problem is usually noise. So, it seems as if you both may have both problems????

The bass problem can't be solved. There is no way it can unless you use a better head unit(of which you'd be surpised how better it would sound even with the cheapest unit out there). On noise, most of the time it is caused from the speaker leads you hooked into. The best way to find this out is to unhook them and listen(which one of you kinda did with the "booster". Reason is that unamplified speaker leads do not need to be sheilded or any special means to run them. So, as they are traveling through out the car, they can pick up noise but you do not hear them. Only when you amplify the signal is when you hear the noise. Still, that should not be a real problem if you have a crossover either on the amp or installed somewhere. Most noise is generated above the 150hz. range. Most of the time you don't want a sub even close to 150hz. rather closer to 80hz instead. So to use a crossover, noise filter, or some sort of bass blocker should do the trick. If you get noise when you have no input, usually it is due to poor ground or power, bad car battery, or bad altinator.

I know you guys do not want to hear it but the real solution is to go aftermarket. Granted, even a little more bass really livens up a stock radio. It's just that it is a waste to put the money in nice subs/amps to only get about a 1/4 of their performance. I've tried and tried with all kinds of vehicles to stay OEM but it never lasted. Every single vehicle I ended yanking the OEM unit for aftermarket. Each time it was a vast improvement. The only car that seemed not too bad was a '00 VW Jetta. The OEM radio was very crisp and clear but it did have the dreaded bass problem when you turned it up. Sometimes I have customers that are satisfied with this type of sound but normally they end up changing the head unit. This is very true now with MP3 and other great things you be had aftermarket.

[Mizery]

I was going to reply to this, but my shit keeps getting messed up. First time, the page refreshed and I lost all my typing. Now, my computer just crashed and I lost 2 paragraphs worth of typing again. So, fuck it. I don't think you completely understand the problem. I am now getting low frequency noise, with crossover on the amp.

As for buying aftermarket or the waste of money on nice subs/amps - I have an old sub and amp that works well. I'm not going to buy new equipment. The whole point for me getting this to work is to not have to spend hundreds of dollars. Also, I have a 6-disc changer in dash right now, and I don't want to give that up.

Maybe I'll clarify the problem more later if I feel like it. Or you can read through all of my posts here and other threads to get a better idea, if you care.

[el es]

Originally Posted by Mizery

I was going to reply to this, but my shit keeps getting messed up. First time, the page refreshed and I lost all my typing. Now, my computer just crashed and I lost 2 paragraphs worth of typing again. So, fuck it. I don't think you completely understand the problem. I am now getting low frequency noise, with crossover on the amp.

As for buying aftermarket or the waste of money on nice subs/amps - I have an old sub and amp that works well. I'm not going to buy new equipment. The whole point for me getting this to work is to not have to spend hundreds of dollars. Also, I have a 6-disc changer in dash right now, and I don't want to give that up.

Maybe I'll clarify the problem more later if I feel like it. Or you can read through all of my posts here and other threads to get a better idea, if you care.

WOW! ¿Are you OK?

at any rate where did you install the crossover? near the head or the amp?

[Mizery]

Thanks for your concern, hehe. Just having a bad time with my computer.

Which crossover? I didn't install any. The stock stereo has them built in for the door speakers and the connector in the trunk. My amplifier also has a lowpass filter, which I have turned on for my subwoofer.

[el es]

Hmmm. Do you ahve a crossover or noise filter? It might be worth installing one inline with the OEM junk. OEM anything wouldn't pass the acid for anything in opinon.

I haven't used a crossover inline before and doubt it would hurt to try but from the way it sounds to you have a dirty line and the fact that the factory uses one at the head end just confirms that Lincoln has their head up their whoohaa. That sort of thing should be near the termination point where it works best to defeat inductance.

IMHO if the filter is any further away than six inches you are inviting noise to the party.

BTW.... I have had some issues with the bords responses lately, as recent as now!