The grid heater relay controls the air intake heater used for cold starts on diesel engines. This guide compares reliable replacement relays and wiring kits compatible with Dodge/Ram Cummins models, highlighting fitment, construction, and wiring differences to help you choose the right part.
| Product | Type | Relevant Fitment |
|---|---|---|
| Custom Battery Cables 6 Gauge with Fuselink | Battery-To-Relay Wiring Kit | 2003-2018 Single Relay Trucks |
| MOTOALL Relay Solenoid Air Intake Heater Grid | Replacement Relay | 1994-2002 Dodge Ram 2500/3500 5.9L |
| Dorman 904-300 Intake Heater Relay | Direct Replacement Relay | Select Dodge / Ram Models |
| Premium Relay Solenoid (Xspeedonline) | Aftermarket Relay | 1994-2002 Dodge Ram 2500/3500 5.9L |
| EATAKWARD 68188401AA Intake Manifold Heater Relay | OE-Number Replacement | 1994-2002 Dodge Ram 5.9L Diesel |
Content Navigation
- Custom Battery Cables 6 Gauge With Fuselink
- MOTOALL Relay Solenoid Air Intake Heater Grid
- Dorman 904-300 Intake Heater Relay
- Premium Relay Solenoid Air Intake Heater Grid (Xspeedonline)
- EATAKWARD 68188401AA Intake Manifold Heater Relay
- Buying Guide: How To Choose The Right Grid Heater Relay Or Wiring Kit
Custom Battery Cables 6 Gauge With Fuselink
Product Type: Battery-to-relay wiring kit for a single grid heater relay. This kit supplies a heavy-gauge cable and built-in fuse link to protect the circuit.
Fitment Notes: Listed for Dodge Cummins Diesel trucks believed to fit 2003-2018 models with a single relay. The listing advises verifying the truck’s relay count and fitment before purchase.
Key Features: Replacement wire from the battery to the grid heater relay, includes a fuselink for safety, compatible with the seller’s battery cable kits, and specified for trucks with one intake heater grid relay.
Technical Considerations: A 6-gauge conductor is typical for high-current heater circuits; the fused link offers protection if the heater develops a short. Verify terminal types and cable length relative to your vehicle harness to ensure proper routing and secure connections.
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MOTOALL Relay Solenoid Air Intake Heater Grid
Product Type: Aftermarket replacement relay for intake heater grid solenoid use in older Dodge Ram diesel models.
Fitment Notes: Specified fitment for 1994-2002 Dodge Ram 2500 with diesel engines. Replaces OEM numbers including Chrysler #68188401AA and Cummins references like 3924594 and 396998.
Key Features: Lists compatibility with OEM reference numbers 68188401AA, 904-308, 56026842, and Cummins part numbers. Designed to replace the original relay on specified vehicles.
Technical Considerations: Confirm the relay pin layout and mounting method match your vehicle. Matching OEM reference numbers suggests functional interchangeability, but check resistance and terminal type if your truck has factory modifications.
Dorman 904-300 Intake Heater Relay
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Product Type: Direct replacement intake heater relay from an established aftermarket parts manufacturer.
Fitment Notes: Marketed as compatible with select Dodge and Ram models. Designed to match the fit and function of the original factory relay used on specified vehicles.
Key Features: Direct replacement design, reliable construction, and made from quality components to promote long service life. Promoted as an ideal solution for relays failing from fatigue or damage.
Technical Considerations: Dorman’s replacement parts often emphasize OEM-like fitment and standardized connectors. Verify physical match to the original relay and confirm expected electrical ratings (coil and contact ratings) for safe operation.
Premium Relay Solenoid Air Intake Heater Grid (Xspeedonline)
Product Type: Aftermarket relay marketed to meet or exceed OEM performance and testing standards.
Fitment Notes: Lists replacement for part numbers including 68188401AA, 904-308, 56026842, 3924594, and 3969987, targeting 1994-2002 Dodge Ram 2500/3500 5.9L diesels.
Key Features: Claimed 100% testing during manufacturing, OEM standard compliance, and a list of interchangeable part numbers. Intended as a no-worry replacement for older intake heater relays.
Technical Considerations: When choosing a premium aftermarket relay, verify the testing claims with available spec sheets and ensure the coil resistance and contact rating match the vehicle’s original relay to avoid overheating or premature failure.
EATAKWARD 68188401AA Intake Manifold Heater Relay
Product Type: OE-number replacement relay designed to match original equipment performance and fit.
Fitment Notes: References OE number 68188401AA and lists compatibility with 904-308, 56026842 and Cummins numbers, indicating fitment for 3924594/3969987 engine applications in older Dodge Ram trucks.
Key Features: Emphasizes OE-quality components, perfect fit and function, and claims to resolve cold-start issues like inlet heater errors by restoring correct relay operation.
Technical Considerations: Manufacturers that advertise OE matching often prioritize form, fit, and functional interchange. Confirm mounting points, terminal types, and whether the relay uses the same electrical ratings as the OE part to ensure compatibility.
Buying Guide: How To Choose The Right Grid Heater Relay Or Wiring Kit
Confirm Vehicle Fitment And Relay Count
Start by verifying your truck’s model year, engine variant, and whether it uses a single or dual grid heater relay. Some wiring kits explicitly note compatibility for single-relay or dual-relay setups. Matching the correct configuration avoids installation issues and ensures proper heater control.
Match OEM Part Numbers And Pin Layout
Use OEM cross-reference numbers listed in product details (for example, 68188401AA, 904-308, 56026842, 3924594). Confirm the relay pinout, mounting style, and terminal type match the original relay. Even relays with identical electrical ratings can fail to fit if pin positioning differs.
Compare Electrical Ratings
Check coil voltage/resistance and contact amperage ratings. Grid heater circuits draw significant current during preheat. Choose a relay or wiring kit rated for the same or higher current than the OEM part to avoid overheating. For wiring kits, verify conductor gauge (6 or 8 AWG) appropriate for the circuit load.
Wiring Kit Features And Safety
Look for fuselinks or inline fuses included with battery-to-relay cables. A properly fused wiring kit protects the battery and harness from short circuits. Confirm cable length and terminal ends to ensure secure connections and correct routing in your engine bay.
Material Quality And Durability
Relays with durable housings, corrosion-resistant terminals, and quality internal components typically provide longer service life. For wiring, stranded copper conductors and quality insulation rated for engine compartment temperatures are important for reliability.
Manufacturer Reputation And Testing
Established aftermarket brands often provide specification sheets or list OEM cross references. Products that state they are tested to OEM standards may offer greater confidence, but validate claims by checking technical data or user feedback specific to your vehicle model.
Comparison Perspectives
- OE-Matching vs Aftermarket Premium: OE-matching relays emphasize exact form and fit, reducing installation friction. Premium aftermarket relays often advertise enhanced testing and materials but require verification of electrical compatibility.
- Relay Only vs Wiring Kit: If the relay itself has failed, a direct replacement is sufficient. If wiring shows heat damage, corrosion, or has been altered, replacing the battery-to-relay cable with a kit that includes a fuselink is advisable.
- Single vs Dual Relay Systems: Wiring kits are specific to relay count; incorrect selection can leave one heater unprotected or improperly powered.
Installation And Diagnostic Checks
Inspect connectors, relay socket, and ground points before replacing the relay. Test coil continuity and measure contact resistance if possible. After installation, verify the grid heater function during a cold-start test and monitor for error codes related to inlet heater circuits.
Long-Term Maintenance Tips
Periodically inspect relay connections and wiring for heat damage, corrosion, or loose terminals. Replace fuselinks if they show discoloration or damage. Maintain battery health to ensure adequate voltage during grid heater operation, as low battery voltage can cause heater malfunctions even with a good relay.
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