Cummins Diesel Engine Intake Heater Grid Relay

What is the purpose of a Heater Grid Relay?

The Heater Grid Relays are switches that open and close circuits electronically. The Heater Grid Relay controls one electrical circuit used to power the engine Heater Grid. The heater grid relay controls the opening and closing contacts in this circuit to activate the operation of the heater grid. 

This Cummins engine is equipped with the heater grid relay that is used to activate the heater grid which is located directly between the air horn and intake manifold. The heater grid heats the incoming air during startup to ensure a quick start in cold weather.

If your Cummins Diesel becomes hard to start or fails to start, it could be the heater grid heater relay. These are MOPAR and Cummins replacement parts that are the same quality as originally installed in your truck. Installing a new heater grid relay is a straightforward process and this will restore the heater grid operation for quick starts on cold mornings! 

Warning signs your Cummins Diesel Air Intake Heater Relay needs to be replaced:

• Longer crank times in cold weather.
• More frequent crank periods before the engine fires.
• Increased white smoke during cold starts.
• A hard to start condition is present during cold weather.

The sole purpose of the heater grid is exactly the same as that of glow plugs. To warm the incoming air charge during cold starts. Diesel engines use either glow plugs and heater grids to aid with cold starts.

How else can I help my diesel engine start on a Cold Morning?

The proper use of a coolant heater will play a big role in the time required to start your engine. When you plug in your truck it heats the engine coolant throughout the engine block. This also raises the temperature of the engine oil which makes it easier to spin over with proper lubrication rates.