4-channel T-harness for 2014–2023 Harley-Davidson® Touring – SoundStream WHD14+ running without the UNLOC kit, to a Hertz SP-series amplifier
This harness does the whole amplifier connection in one part. It takes all four speaker-level outputs from a SoundStream WHD14+, feeds them to a Hertz SP-series amplifier, and returns the amplifier's output into the factory speaker harness. The thumb control module that came with your head unit keeps working exactly as it does now. Nothing on the bike is cut or spliced.
Two things decide which harness you need: your head unit and your amplifier. This one is for a WHD14+ running on its own, into the Hertz SP series. If your WHD14+ has the WHD.UNLOC kit fitted, or you are running an HDHU.V2, you need the Maestro-integrated Hertz version. Running a Cicada Audio® amp instead? See the Cicada version.
Who This Is For
You are running, or about to run, a SoundStream WHD14+ in the fairing of a 2014–2023 Harley-Davidson® Touring bike, without the WHD.UNLOC kit, and you want a Hertz SP-series amplifier mounted in the fairing behind it. That is the standard setup on a bike with fairing speakers and no factory amplifier. It also covers a bike that had factory Boom!™ amplification, where the Hertz is going in to replace that amplifier outright – depending on how your bike is wired that may need a factory amp bypass harness as well, so call us on 07 3350 1354 before ordering if that is your build.
What This Is Best For
- Built for the Hertz SP series – the amplifier end is terminated for the SP-series input, so it drops straight onto a Hertz SP 4.500 or SP 4.900 without hand-wiring the input plug. Step up from the 4.500 to the 4.900 later and the harness carries over.
- Signal out and speaker return in one loom – a true T-harness, not a one-way signal lead. Four channels of speaker-level output go to the amplifier, and the amplifier's output comes back through the harness into the factory speaker loom.
- Your thumb controls keep working – volume, track skip and call answer/end run through the thumb control module supplied with the WHD14+, which this harness leaves untouched. Adding the amplifier does not cost you the handlebar controls you already have.
- Nothing gets cut – head unit loom, OEM speaker harness and amplifier input plug all stay factory. Spliced-in signal tails are the most common reason a used bagger's audio has to be unpicked and rebuilt.
Which Harness Do You Need?
Every one of these suits 2014–2023 Touring, so the model year will not tell you which to order. Two things decide it. Your head unit: a WHD14+ running on its own has no Maestro module to connect to – that is this harness. An HDHU.V2, or a WHD14+ with the WHD.UNLOC kit, needs the extra Maestro leg and takes the Maestro-integrated version. Your amplifier: this harness is terminated for the Hertz SP series; for Cicada Audio® amps see the Cicada version. Still running the factory Harley radio? Neither of these suits – call us on 07 3350 1354.
The Bottom Line
Four channels out, amplifier output returned to the factory loom, thumb controls untouched, and the whole thing reversible. It removes the stage of the install where noise problems get introduced. Add to cart above – the amplifier still needs its own power and earth run, covered below.
Fitment
| Head Unit | Configuration | Years |
|---|---|---|
| SoundStream WHD14+ | Running without the WHD.UNLOC kit | 2014–2023 |
Running a WHD14+ with the UNLOC kit, or an HDHU.V2? See the Maestro-integrated version.
How the Harness Sits in the System
The loom has three ends rather than two. The head unit end takes four channels of speaker-level output from the WHD14+'s own Class-D output section and carries them to the amplifier's input stage without converting to line level first. The amplifier end returns the Hertz amplifier's speaker output back into the factory harness, so the OEM speaker wiring downstream of the radio is used exactly as Harley-Davidson® built it. On the road: fewer conversion stages between source and amplifier means fewer places for noise to enter, and it shows up most at idle, when alternator whine is at its most audible through a fairing.
There is no Maestro leg on this harness, because a WHD14+ running without the UNLOC kit has no Maestro module to connect to. Handlebar control comes from the thumb control module supplied with the head unit, and that is independent of this loom. On the road: volume, track skip and call answer/end work from the bars exactly as they did before the amplifier went in – what you do not get is on-screen gauges or advanced button mapping, and those need the UNLOC kit rather than a different harness.
Terminations are machine-crimped, strain-relieved and continuity-tested before dispatch. On the road: hand-soldered joints work-harden under constant fairing vibration and fail intermittently – a channel that drops out over rough bitumen and then tests perfectly back in the workshop.
Technical Specifications
| Type | 4-channel T-harness – head unit to amplifier, amplifier to OEM speaker loom |
| Head Unit Compatibility | SoundStream WHD14+ without the WHD.UNLOC kit |
| Amplifier Compatibility | Hertz SP-series amplifiers |
| Channels | 4 |
| Signal Level | Speaker level |
| Handlebar Controls | Basic thumb control retained via the module supplied with the WHD14+ |
| Module Integration | None – for Maestro RR/RR2 builds see the Maestro-integrated version |
| Amplifier Location | Fairing mount |
| Carries Amplifier Power / Earth | No – separate power and earth run required |
| Vehicle Fitment | 2014–2023 Harley-Davidson® Touring |
| Warranty | 2 years |
In the Box
- 1 × MAA Soundstream-to-Hertz 4-channel T-harness, assembled and tested
The amplifier power and earth kit is sold separately.
Completing the Install
The amplifier needs its own power and earth run from the battery – the 8-Gauge Premium Fairing-Mounted Amp Power Harness with Disconnect is the matching part for a fairing-mounted amp, and its inline disconnect turns fairing removal into a one-plug job.
Because the harness hands the amplifier's output back to the factory loom, fairing speakers are already taken care of. Rear speakers depend on how your bike is wired – some configurations run the rear channels through to the saddlebags or Tour-Pak® on their own, and some need a separate backbone harness to get there. The SaddleTramp BC-9720 Rear Speaker Backbone Harness is the usual answer, with the Deluxe Rear Speaker Split Backbone Harness for builds running Tour-Pak® and saddlebag speakers together. If you are not sure which applies to your bike, call us before ordering.
Australia Shipping:
- Under $500 → $19.95
- $500–$2,500 → $14.95
- $2,500 and above → FREE
- Bulky items → +$25 surcharge (waived once your order reaches $2,500)
Fast dispatch from Brisbane. In-stock orders placed before 1pm AEST usually ship the same business day.
Change of mind: Request a return within 30 days of delivery. The product must be unused, unopened and in its original sealed packaging, valued at $50 or more, and you'll need an RMA number from us before sending anything. Return freight is yours, and a restocking fee of up to 15% may apply – we'll confirm any fee before the return is accepted.
Not returnable for change of mind: opened, installed or test-fitted items, special-order and custom products, custom harnesses, completed tuning, gift cards and items under $50.
Fitment: If we confirmed fitment in writing based on accurate bike details and it doesn't fit, we'll put it right and cover reasonable freight. Not sure? Ask us before you order – we're happy to help.
Faulty, damaged or wrong item: Contact us first with your order number. Faults follow our RMA and warranty process, and none of this affects your rights under the Australian Consumer Law.