Pierce Cummins ISL DEF Head Unit
PIERCE CUMMINS ISL DEF HEAD UNIT
ORDERS PLACED BEFORE 3PM EST WILL SHIP SAME DAY
WARRANTY
1M MILES OR 1 YEAR
PRODUCT DESCRIPTION
This is a Remanufactured, Tamerx DEF Head Unit, Tamerx part number 4310-11-24 ( OEM Part Number 3329295 ). This part is primarily made for a Cummins ISL, and comes with a One Million Miles or One Year Warranty. For additional warranty info Click Here
Additional Notes: DEF Header, 40 MICRON, 11"
OEM NUMBERS
| Primary OEM | 3329295 |
| Additional OEM | 3329295 |
ADDITIONAL DETAILS
| CONDITION | Remanufactured |
| UPC / Barcode | 00840490541061 |
| WEIGHT | 8.00 LBS |
SHIPPING OPTIONS
Ship Weight : 8.00 LBS
UPS Ground, 2nd Day Air, Next Day Air
SHIPPING POLICY
Tamerx Diesel Products ships via UPS Ground. Next day air shipping can be arranged for a reasonable price of anywhere from $50.00 - $100.00 depending on the weight of the product and your location. We will do everything we can to make sure that you get the service you need. We understand how important it is to receive your order as quickly as possible.
In most cases Tamerx Diesel Products only needs one address, as long as your product is shipping to the same location as your billing information. In order to eliminate credit card fraud, your billing information must match the credit card you provide.
The terms, conditions, and details of our warranty vary from product to product. Specific warranty details can be found below.
Tamerx Diesel Products provides a replacement warranty on all of our parts. The duration and mileage limitations of the warranty vary by product and are specified on the product's detail page/item listing.
Please note that the warranty covers replacement of the part and the cost of shipping the replacement part to you only. It does not cover any shop, labor, towing, or any similar or related costs. This is not a "money back guarantee".
If you experience a problem with your part or it is not functioning properly, the correct warranty procedure is to call us at (510) 257-1777 (8:00 AM - 5:00 PM ET Monday through Friday). Be sure to have your order number and/or other relevant order information ready so we can easily locate your order and resolve your issue as quickly as possible. From that point, we will review with you any troubleshooting steps that may need to be taken and other areas or systems that can be checked to rule out external problems contributing to your part's issue. If a replacement is determined to be necessary, we will then arrange for your replacement part to ship out ASAP and issue any necessary return shipping labels and/or documents.
As is the case for the majority of the diesel products sold on Tamerx Diesel Products, your part's warranty is active as soon as you install it. In some other cases, warranty activation is contingent upon you sending us your core (i.e., your old part). Tamerx Diesel Products will provide you a return shipping label for parts that have a warranty with a core return condition. When we have received your core return, the part's warranty coverage begins. We reserve the right to void the product warranty if your core is not received within the allotted time, or if it isn't received at all. If the warranty for the diesel part you are purchasing has a core return requirement, it will be clearly noted on the product detail page/item listing.
What is a Core Charge?
A core charge (also called "core deposit") is similar to the deposit you might pay for a can or bottle of soda and is a standard requirement in the auto parts industry. For example, in many states, to promote recycling, you pay a deposit when you purchase a can of soda and receive your deposit back when you return the empty can. Many automotive parts have a core charge, or core price, that works in essentially the same way as a soda can deposit.
30 Day Core Charge Hold
You authorize Tamerx Diesel Products, to hold your credit card for the specified core charge amount and that you agree to return your core with 30 days of receiving the purchased part. When we have received your core return, the hold is released and the core charge payment is canceled.
The customer, or parts buyer, is responsible for any shipping costs associated with core returns unless otherwise specified in the product listing/detail page. Tamerx Diesel Products offers prepaid UPS shipping labels (SKU numbers UPS-CR1 and UPS-CR2) for use in returning your core that are available for purchase on our website during your shopping/order process.
The shipping label you will need to use for the core return is dependent upon what part you are purchasing. UPS-CR1 is good for cores weighing up to 20 pounds. UPS-CR2 is appropriate for shipping cores weighing 21 pounds or more. You must include enough information with the core return that clearly identifies it as a.) a Core Return, and b.) contains enough information we can use to clearly associate the core return with your order. Including a copy of the invoice or packing slip that came with the original shipment, clearly marked "Core Return", is ideal. Alternately, you can include a note marked as "Core Return" that includes your order number, full name and address, and phone number or other contact information. Failure to include this information with your returned core will most likely delay any due core credit being issued and/or delay any applicable warranty activation. Core returns need to be for the exact part purchased and cannot be damaged. Substituting another part in place of the part you have purchased is not acceptable.
All fluids must be drained.
If you have purchased a set or a parts package, you will need to return cores for all components of the set. For example, if you have purchaed a high pressure oil pump with an IPR valve, you will need to return both HPOP and IPR valve cores to receive proper credit. If you have purchased an EGR cooler/EGR valve package, your core return must consist of an EGR cooler core and an EGR valve core, or core credit will not be given.
Core Charges are often mandated by state legislature, and, as such, the actual core charge and taxes on the charge may vary depending on the state in which you buy your part. The Tamerx Diesel Products core charge presented to you online today with your item is representative of the most common core charge.
Reliable DEF system function is supported by the Pierce Cummins ISL DEF Head Unit: OEM 3329295, a direct-fit replacement for compatible Pierce emergency vehicles. Built to OEM standards, this unit tracks diesel exhaust fluid level, temperature, and quality to help maintain emissions compliance and consistent aftertreatment operation. Its durable construction is designed to withstand demanding service conditions, protecting the exhaust system and overall engine efficiency. Choosing an OEM DEF head unit helps reduce compatibility issues and ensures long-term dependability. This component is a proven solution for keeping Pierce Cummins-powered apparatus operating smoothly and without interruption.
PEOPLE ALSO ASKS | BLOG(S)
Modern diesel engines rely heavily on advanced emissions control systems to stay compliant with environmental regulations. One of the key components in this system is the DEF (Diesel Exhaust Fluid) Head Unit—and for Pierce fire apparatus or heavy-duty vehicles equipped with the Cummins ISL engine, the OEM 3329295 DEF Head Unit plays a vital role.
So, what exactly makes up this component, and why is each part important?
Key Components of the 3329295 DEF Head Unit
- DEF Level Sensor
- Constantly monitors the volume of DEF in the tank and communicates this data to the engine control module. This helps prevent low-DEF situations that could trigger engine derate or system faults.
- Temperature Sensor
- Measures the temperature of the DEF fluid. Since DEF can freeze in low temperatures, the sensor helps manage heating functions and ensures the system operates within safe parameters.
- Internal Filter (Approx. 40 Microns)
- Screens out debris, crystals, and other contaminants before they enter the downstream dosing system. Clean DEF helps extend the life of injectors and SCR components.
- Suction or Pickup Tube
- Draws DEF from the bottom of the tank and sends it toward the injection system. It ensures a steady supply of fluid when needed by the SCR system.
- Return Port
- Allows unused or excess DEF to flow back into the tank. This helps maintain proper fluid circulation, prevents overpressure, and supports consistent system performance.
- Electrical Connectors
- Facilitate communication between the sensors in the head unit and the vehicle’s ECM (Engine Control Module). These connections are vital for diagnostics, system alerts, and automated adjustments.
- Housing, Flange, and Seals
- The outer body and mounting structure of the head unit ensure a secure, leak-proof installation onto the DEF tank. The sealing elements prevent contamination and preserve internal component integrity.
Each part of the 3329295 DEF Head Unit works together to ensure DEF is clean, properly monitored, and delivered consistently. If any of these components fail, it could lead to:
- False warning lights or DEF level errors
- Frozen or overheated DEF fluid
- Contaminated DEF reaching sensitive injectors
- System malfunctions or engine derate
By maintaining this head unit in good condition, operators ensure optimal emissions performance, system longevity, and full compliance with emission standards.
The DEF (Diesel Exhaust Fluid) head unit is a vital part of your vehicle’s emissions system. It contains sensors that measure DEF level, temperature, and fluid quality. When these sensors fail or produce false readings, it may be tempting to try servicing or cleaning the unit to restore functionality.
Can You Clean a DEF Head Unit?
The short answer: external cleaning is possible, but internal servicing is not recommended.
While the unit is sealed and designed to operate in harsh environments, here are some safe cleaning practices:
- Gently remove crystallized DEF
- buildup from external ports and tank fittings
- Use only distilled water
- never apply chemicals or cleaners to the head unit
- Avoid pressure washing
- near the electrical connector or sensor housing
- Inspect for connector corrosion
- and clean contacts with appropriate electrical-safe products
- Do not disassemble
- the unit — internal components are not serviceable
If the unit is still showing incorrect readings after cleaning and connector checks, replacement is typically the only solution. Internal sensors and heaters cannot be repaired.
It is engineered to withstand vibration, high heat, and demanding duty cycles.
Delays may cause emissions faults, reduced performance, and downtime.
No, it must be replaced with a new OEM unit when defective.
It is mounted directly inside the DEF tank to measure fluid conditions.
Cummins DEF Head Units
