Product Description
Upgrade your cold-weather performance and restore reliable starts with the genuine CUMMINS 3929108 Intake Air Heater Grid. This factory-engineered grid heater is purpose-designed to warm the incoming intake air for your 1989-1998 5.9 L 12-valve Cummins diesel, reducing white smoke and ensuring smoother startup in harsh conditions. The direct-fit design means no modifications, and you’re backed by Cummins’ reputation for durability and precision fitment.
Fitment Details
- Engine: 5.9 L 12-valve (6BT) Cummins diesel
- Model years: 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998
- Chassis: Dodge Ram 2500/3500 (and equivalent off-highway applications) with separate grid heater/plenum configuration.
- Note: Does **not** fit 1998.5-2002 24-valve VP44 or 2003-2007 common-rail 5.9L setups — those use a different heater assembly (e.g., part 3969987)
Cross-Reference / Alternatives
When installing this grid heater, you’ll often pair it with the intake heater grid gasket CUMMINS 3969988.
Also note that this part supersedes earlier grid heater switch relays such as CUMMINS 3913348.
Why Choose Genuine Cummins?
Choosing the genuine Cummins branded grid heater ensures optimum engine performance, reliable cold starts, proper fitment and backed warranty protection. Unlike aftermarket units, there is no guess-work or compromise when it comes to fit, finish or durability.
FAQ
Will this fit my 1989–1998 5.9 L 12-valve Cummins?
Yes—it’s the OE grid heater for most of those years when the engine uses a separate intake horn/plenum and grid heater. Always confirm your intake/plenum style matches.
Will it fit 24-valve (1998.5–2002) or common-rail (2003–2007) 5.9L Cummins engines?
No—those later engines typically use a different heater/grid assembly (for example part 3969987) and may require two gaskets.
What are signs of a failing heater grid?
Hard cold starts, lots of white smoke on startup, or diagnostic tests showing no current draw to the heater grid.
Is a new gasket required when swapping this heater grid?
Yes—Cummins recommends replacing the intake heater grid gasket (CUMMINS 3969988) when installing this grid heater to ensure proper seal and performance.
| Specifications for CUMMINS 3929108 | |
|---|---|
| Part Number | 3929108 |
| UPC / GTIN | N/A (no published UPC/GTIN found) |
| Shipping Info | Approx. dimensions 6.63″ H × 6″ L × 3″ W; weight ~1.55 lbs. |
| Cross Reference | Includes gasket CUMMINS 3969988; previously superseded relay CUMMINS 3913348. |
| E-Codes / Regulation | No specific emissions E-code listed for this part. |
| Prop 65 Warning | This product can expose you to chemicals known to the State of California to cause cancer and birth defects or other reproductive harm. For more information, visit P65Warnings.ca.gov. |
