The Wacker Neuson Glow Plug Relay is a genuine OEM glow plug relay designed for the APT4S and APT4T pump series, including standard and cold weather configurations. As a factory-sourced component, it meets the exact electrical specifications required by Wacker Neuson for correct cold-start operation across these pump models. Fitment covers the APT4S Pump with Skid, APT4T Pump with Surge Brake, APT4T Pump with Electric Brake, and their respective cold weather variants. Replacing a failed relay with the correct OEM part ensures your pump starts reliably and operates as intended.
Key Features
- OEM-Matched Switching Specification — Sourced directly from Wacker Neuson, this relay meets the precise voltage and current switching thresholds required to activate the glow plug circuit correctly.
- Drop-In Electrical Connector Fit — Designed to connect directly to the existing wiring harness with no splicing or adapter work needed.
- Broad APT Series Coverage — Fits APT4S and APT4T pump models in both standard and cold weather configurations, covering surge brake and electric brake variants.
- Cold-Start Reliability — A functioning glow plug relay ensures the engine's glow plugs receive the correct signal at startup; a failed relay causes hard starts or no-start conditions, especially in cold conditions.
- Electrical Safety Compliance — As a genuine OEM part, this relay is built to Wacker Neuson's electrical safety standards, reducing the risk of relay failure that could damage the glow plug circuit or related wiring.
The glow plug relay controls the activation of the glow plugs in a diesel engine, sending power to the plugs for a timed period before and during cranking to pre-heat the combustion chambers for a clean cold start. Without a properly functioning relay, the glow plugs may not activate at all, leading to difficult starts, excessive cranking, or a complete no-start condition — particularly in cold weather. Over time, relay contacts can burn out or the internal switching mechanism can fail, making it a common service item on diesel-powered pumping equipment.
Part Details
| Part Number | 5200020303 |
|---|---|
| Brand | Wacker Neuson |
| Part Type | Genuine OEM |
| Description | Glow Plug Relay |
Compatibility & Fitment
| Name | Model | Machine Number |
|---|---|---|
| APT4S Pump w/Skid | APT4S | 5200018977 |
| APT4T Pump, Surge Brake | APT4T | 5200019643, 5200019644 |
| APT4T Pump, Surge Brake, Cold Weather | APT4T CW | 5200019792, 5200019793 |
| APT4S Pump w/Skid, Cold Weather | APT4S CW | 5200019798 |
Verify Before You Order
Fitment is machine-number and revision-specific; always confirm your model and serial number against the fitment list.
Why Buy From DHS Equipment
Every part is verified against the manufacturer's part number before it ships, so what you order is what arrives. We carry parts from leading OEM brands and our own DHS Quality Parts line of professional aftermarket components. Need help finding the right part? Our team is available to confirm compatibility whenever you need it. Orders are processed fast to keep your jobs on track. We don't just sell parts. We keep you jobsite ready.
Questions? Contact our team at [email protected] or 866-611-9369 — DHS Equipment is here to help you maintain peak performance.
