# 21857958 Wiring Harness | Genuine Volvo Penta Part

## 🔧 Product Description

A genuine wiring harness used in the DPH-C power-trim pump assembly. It connects the trim motor, relays and drive-control wiring so the sterndrive can raise and lower under helm command.

## 🚤 Compatibility

Typically suits:

-   Volvo Penta DPH-D1
-   Volvo Penta D6-330A-F
-   Volvo Penta D6-370A-F
-   Volvo Penta D4-260A-F
-   Volvo Penta D4-300A-F
-   Volvo Penta D6-300A-F
-   Volvo Penta D4-225A-F
-   Volvo Penta D6-300A-G
-   Volvo Penta D6-340A-G
-   Volvo Penta D6-380A-G
-   Volvo Penta D6-400A-G
-   Volvo Penta D6-400A-F
-   Volvo Penta DPR-D
-   Volvo Penta D4-150A-G
-   Volvo Penta D4-230A-G
-   Volvo Penta D4-270A-G
-   Volvo Penta D4-300A-G

-   **Engine Family:** DPH, D, DPR
-   **HP Range:** 150-400 HP
-   **Year Range:** Approximately 2009 - 2018

## ⚙️ Key Features

-   Factory branch lengths and keyed connectors
-   Engine-grade conductor insulation and protective covering
-   Correct terminal sizes and circuit routing
-   Supports diagnostics, alarms or control functions
-   Engine type: Volvo Penta Aquamatic Duoprop sterndrive

## 🔌 Function

Distributes electrical power, ground and control signals between the specified engine, drive, sensor or control components.

## ⚠️ Common Signs of Failure

-   Several unrelated electrical fault codes
-   Voltage drop or open circuit
-   Corroded, loose or moisture-damaged terminals

## 🛠️ Service Notes

-   Compare the new harness with the old one before fitting — check the connector types, the number of pins and the branch lengths, and lay it out alongside the old loom to confirm every branch reaches its component
-   Disconnect the batteries before unplugging or fitting a harness, and support the loom as you work so its weight never hangs on a connector or a bulkhead grommet
-   Route it along the original path and secure it with the original clips and ties, clear of hot exhaust surfaces, sharp edges and anything that moves; leave a service loop at each connector rather than pulling a branch tight
-   Push every connector home until the lock latches and protect the joints with a marine dielectric grease — an intermittent electrical fault is far more often a partly seated or salt-corroded pin than a broken wire
-   Renewing the harness is the right repair where insulation is chafed, brittle or oil-soaked, or where corrosion has tracked inside the connector bodies; patch repairs in a damp engine bay tend to fail again, and any single conductor that is repaired should be joined with tinned marine cable of the same gauge, a proper crimp and adhesive-lined heat-shrink

## 🔄 Supersession & Cross Reference

### OEM Supersession Chain

-   21857958 → Supersedes 21767818

### OEM / Related Numbers

-   21767818 earlier number superseded by this part
-   21831047 - trim pump
-   3861575 - trim-pump motor
-   3861577 - electrical connector
-   3861578 - O-ring
-   3861570 - oil reservoir
-   3861572 - reservoir cap
-   3858083 - mounting bracket
-   21767816 - trim relay
-   21721548 - hydraulic hose assemblies
-   21721550 - hydraulic hose assemblies

## 📦 Condition

-   Genuine Volvo Penta part
-   Brand new
-   Supplied in original or equivalent packaging

## Details

- **Price:** 995.19 AUD
- **Vendor:** Volvo Penta
- **Type:** Electrical & Wiring
- **Tags:** Volvo Penta

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 995.19 AUD | In stock |

## Images

- 21857958 Wiring Harness | Genuine Volvo Penta Part

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> Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/products/21857958-wiring-harness-genuine-volvo-penta)
> Updated: 2026-09-19