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Wiring some bass in my car, wtf!?

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  • Wiring some bass in my car, wtf!?

    I'm trying to hook up a speaker box in the trunk, I had it on my old Lincoln and it worked great but I haven't been able to get it to work with the current car. I tested the speakers and they work, I replaced the amp, but nothing, I tried all versions of connections and noticed two things, when I fade to the rear I get no sound, when I fade to the front I get all speakers except the box. The box has power and the remote works. I get sound but it's real low muffled sound.

    i think the wiring is wrong and I'm wondering if anyone has a wiring schematic so I can't just wire the proper wires together and maybe then this thing will work. It's annoying the crap out of me.
    Attached Files

  • #4
    Looking at the original date on this post you've probably long-since resolved this issue, but being that there are no replies directly addressing your question to date, I'll go ahead and put this in here for future reference of others (or even yourself if somehow still needed). I've been doing aftermarket car audio since the mid/late 90's & have been doing so professionally since late 2005 as an M.E.C.P. certified installer, so I hope someone finds this helpful. (That said, being that I cannot directly diagnose/test your specific car in person, this information is being given as reference material ONLY, and NOT as actual advice on what you personally should do in your specific car/case. I therefore will accept NO personal liability for how you elect to use it, or any damage that you might cause by not knowing what you're doing. If you're unsure of how to proceed, consult your local certified aftermarket 12v accessory installation shop.)

    The good news is that the style of aftermarket radio harness adapter that you have in your pic is designed to accommodate all necessary wiring connections as follows:
    (P.S. a quality-made adapter will often be labeled directly on the wires; likely for all us sad-souls out there who are colorblind, lol)

    Power Connector (larger wide/flat rectangular plug): Constant (+) 12v power (Red), Switched (+) 12v Power (Yellow), (-) Negative Chassis Ground (Black) (not available on all models as those radios are typically grounded through the metal mounting hardware & dash), (+) Power-Antenna Remote Turn-On (Blue or Blue w/Stripe, depending on model) (not available on all models), (+) Amplifier Remote Turn-On (Blue or Blue w/Stripe, depending on model) (not available on all models) (side note: Amp & Antenna are sometimes conjoined using the solid blue or blue w/stripe wire depending on Year, Make, and Model & harness adapter manufacturer), Illumination (+) Trigger (Orange) (not available on all models), Illumination Dimmer (+) Trigger (Orange w/White Stripe) (not available on all models), Illumination Dimmer (-) Trigger (Orange w/Black Stripe) (not available on all models).

    Speaker Connector (smaller square plug): (+) Front-Left Speaker (White), (-) Front-Left Speaker (White w/Black Stripe), (+) Front-Right Speaker (Grey), (-) Front-Right Speaker (Grey w/Black Stripe), (+) Rear-Left Speaker (Green), (-) Rear-Left Speaker (Green w/Black Stripe), (+) Rear-Right Speaker (Purple), (-) Rear-Right Speaker (Purple w/Black Stripe).

    According to the description you gave as to what you're experiencing when you fade/balance the speaker outputs on your radio, it would appear that either someone mis-wired to speaker connections at the radio or possibly even at the amp if an amp-bypass harness was used during the original install. A simple way to know is to either use a DMM (Digital Multi-Meter) to test which wires are receiving an A/C voltage signal out of the radio when the balance/fade is adjusted to different positions. In the absence of a DMM, you can always use one of my preferred methods for quickly identifying speakers by using a pair of alligator clips attached to wire leads & a 9v battery to "pop" the speakers one at a time (either using a momentary switch inline with the positive wire & a 9v battery terminal, or simply "tapping" the wires to the terminals on the battery briefly; switch, alligator clips, & battery terminal are optional, but definitely make it easier). Once you've located the correct wires, it shouldn't be too terribly hard to correct the mis-wiring of your adapter/speakers (fyi, wire polarity matters; wiring your speakers out of phase will cause signal cancellation and result in poor speaker "performance" for the listener).

    Quick caveat: The one downside to trying this in a factory JBL sound system equipped Mark VIII model is that the main woofers are typically wired in parallel to one another (separated by left/right), and the tweeters are wired to be independent of them when fading/balancing the sound around the vehicle (if my memory serves me correctly; it's admittedly been a while since I diagnosed one of these, so I admit that I could be remembering that backwards/incorrectly). That aside, if you're trying to get an audio feed out of your "rear speaker wires" for your sub-box (rather than simply using RCA's) and you're not getting any output (or limited output) then your speaker connections have likely not been done correctly at some point along the process.

    As a general rule of thumb, I always recommend using high quality RCA's for these types of connections as most aftermarket radios tend to have built-in RCA outputs for this very purpose. Quality-made RCA wires tend to have good signal shielding to limit/avoid/mitigate the potential for what is known as "inducted noise" (i.e. alternator whine) generated from the factory wiring (although depending on the year/make/model and potential electrical issues the car might have, it may not make much of a difference overall); but if that's not an option for you, then hopefully you'll find this info helpful.

    (P.S. Unless you're well versed both in how to test factory electrical circuits in the car, and also how to read the wiring diagram of the aftermarket radio (not all are adequately labeled for the novice/inexperienced installer) I DO NOT recommend attempting to connect the "Illumination Dimmer" wires (Orange w/White and/or Orange w/Black) to your aftermarket radio for ANY reason. If your aftermarket radio IS equipped with an "Illumination trigger wire" for dimming the brightness of the display at night, most of them typically just want to see activation of the positive (+) trigger found on the Orange wire ONLY for that purpose).

    Best of luck with it & best wishes. Hope this helps.


    • #5
      This is a great post, D!

      Welcome! and thank you for taking the time to post this information. Last I heard, Mike P was still not completely satisfied with his solution, but I haven't heard any updates for maybe a year or so. No doubt this will be valuable information for him.
      Mike Martin

      1997 Mark VIII LSC 5.0
      2001 Dodge Dakota