# 1578657 Make Contact/Diff | Genuine Volvo Penta Part

## 🔧 Product Description

This genuine Volvo Penta make contact/diff is a precision electrical sensing and indication component used in the electrical warning or differential-pressure circuit. It is manufactured to the original Volvo Penta dimensions and interface requirements so the sender or switch retains the specified electrical range, mounting depth and signal relationship. In service, it changes electrical contact state when the monitored differential or pressure condition reaches its switching point. Fitment is controlled by the exact engine or product configuration and serialised parts list; confirm OEM number 1578657 against the installed assembly before ordering.

## ⚙️ Key Features

-   Genuine Volvo Penta OEM make contact/diff
-   OEM part number 1578657
-   Check supply voltage, earth integrity, connector condition and circuit continuity before condemning the sender or switch; test the complete indication circuit after installation.

## 🔌 Function

Changes electrical contact state when the monitored differential or pressure condition reaches its switching point. Check supply voltage, earth integrity, connector condition and circuit continuity before condemning the sender or switch; test the complete indication circuit after installation.

## ⚠️ Common Signs of Failure

-   Gauge or warning indication is missing, intermittent, permanently active or clearly inaccurate
-   Reading does not change smoothly with the actual level, pressure or operating condition
-   Open circuit, short circuit, excessive resistance or unstable continuity at the sender/switch
-   Corroded, loose, burnt or moisture-contaminated terminals and connector pins
-   Signal changes when the harness is moved, the engine vibrates or the component temperature changes

## 🛠️ Service Notes

-   This is a 'make' contact - normally open, closing only when the monitored differential/pressure condition is reached. Test continuity across the terminals with the triggering condition actually present, not at rest, or the switch will appear faulty when it is not.

## 📦 Condition

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

## Details

- **Price:** 247.15 AUD
- **Vendor:** Volvo Penta
- **Type:** Sensors & Senders
- **Tags:** Volvo Penta

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 247.15 AUD | In stock |

## Images

- 1578657 Make Contact/Diff | Genuine Volvo Penta Part

---

> Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/products/1578657-make-contact-diff-genuine-volvo-penta)
> Updated: 2026-10-20