Is Your 2004 Blazer S10 or Jimmy S15 Running Rough?
If you’re dealing with frustrating engine problems, a faulty Engine Control Module (ECM) is often the culprit. As a mechanic with over two decades of experience diagnosing these GM trucks, I’ve seen firsthand how a failing computer can turn a reliable vehicle into a source of constant headaches. You might be experiencing issues that seem random and are difficult to pin down, leaving you stranded or worried about your truck’s dependability.
Common Symptoms of a Failing GM ECM
A bad ECM can manifest in numerous ways. If you’re noticing any of the following, it’s a strong indicator that the brain of your engine is in trouble:
- โ Check Engine Light is on with communication error codes.
- โ Engine stalls unexpectedly or struggles to start.
- โ Noticeable decrease in fuel economy.
- โ Rough or erratic idling and poor acceleration.
- โ Transmission shifting issues or harsh engagement.
- โ Complete no-start condition where the engine cranks but won’t fire.
The Direct Solution: A Pre-Programmed 2004 Blazer S10 ECM
Don’t let a bad module keep you off the road. This replacement Electronic Control Module, part number 89017739, is the definitive solution. We take all the guesswork and hassle out of the repair. Before we ship the part, our technicians will program it with the latest official GM software updates, specifically calibrated to your vehicle’s unique Vehicle Identification Number (VIN). This ensures that when it arrives, it’s a true plug-and-play component, ready to restore your truck’s performance and reliability.
Expert Pro Tip from a 20-Year Veteran Technician
“A customer’s 2004 Jimmy S15 came into my shop last month with intermittent stalling and no-start issues. He had already replaced the ECM himself, but the problem returned. The real issue wasn’t the module itself, but water intrusion. The cowl seal above the firewall was leaking, allowing water to drip directly onto the ECM connectors, causing corrosion and short circuits. Before you install your new module, take five minutes to inspect the wiring harness connectors for any green or white crusty buildup. Clean them thoroughly with a contact cleaner and a small brush. This simple step can prevent a repeat failure and save you hundreds of dollars.”
Plug-and-Play Installation: No Dealer Visit Required
You can perform this replacement right in your own driveway with basic hand tools. By ordering a pre-programmed module, you bypass the need for expensive dealership programming or specialized scan tools.
- Safety First: Disconnect the negative terminal from your vehicle’s battery.
- Locate the ECM: On the 2004 Blazer S10 and Jimmy S15, the ECM is typically found in the right-hand (passenger side) front of the engine compartment.
- Disconnect the Harnesses: Carefully release the locking tabs and unplug the wiring harness connectors from the old module.
- Remove the Old Module: Unbolt the old ECM from its mounting bracket.
- Install the New Module: Bolt your new, pre-programmed ECM into place and securely reconnect the wiring harnesses. Ensure they click into place.
- Reconnect the Battery: Reattach the negative battery terminal. Your truck is now ready to start.
Guaranteed Compatibility
This module is a direct replacement for part numbers 89017739 and 12586243. It is compatible with a wide array of 2004 GM vehicles, including the Chevrolet Blazer S10, GMC Jimmy S15, Sonoma, Astro, Safari, and many others as detailed in the fitment list. Providing your VIN during checkout is essential for us to deliver a perfectly matched and updated module for your specific vehicle. Get your truck running right again with a reliable, professionally programmed ECM.