Diagnose Mitsubishi Eclipse Blower Shutdown in 15 Minutes

Q: Symptom 2: Fan Does Not Work on ANY Speed

Probability: ~25% of cases. Causes: Blown fuse, failed motor, or broken wiring. Quick Test: First, check the HVAC/Blower fuse in the interior fuse box (often 25A or 30A). If it's good, listen for a "click" or hum from under the dash when you turn the fan on—if you hear it, the motor is likely seized. Cost: Motor: $80-$150; Fuse: $5. Repair Time: Motor replacement: 1-1.5 hours. Symptom 3: Fan Works Intermittently on All Speeds Probability: ~10% of cases. Causes: Failing motor (brushes wearing o

Q: Symptom 4: One Specific Speed (Not High) is Missing

Probability: ~5% of cases. Cause: Specific circuit failure within the resistor or a problem with the control switch. This is less common but points directly to the resistor pack. Diagnosis requires a multimeter test at the resistor connector. 4. Diagnostic Decision Tree Follow this text-based flowchart: Does the fan blow at all? NO → Check the HVAC/Blower fuse. If blown, replace it. If it blows again, you have a short circuit (likely a pinched wire or failing motor). YES → Does it work on AL

Q: Q: Why does my blower resistor keep burning out every year?

A: This is a classic sign of a blower motor on its last legs. A motor with worn brushes draws higher amperage (amps), which overheats and destroys the resistor. The real fix is to replace the motor and the resistor together.

Author: Mike, ASE Master Certified Technician (HVAC Specialist, 18 years experience)

1. Overview

This guide will help you pinpoint why your Mitsubishi Eclipse’s blower fan has stopped working or only works on certain speeds. With a basic multimeter (around $15) and 15-30 minutes, you can isolate the problem in about 80% of cases without needing a shop. The goal is a fast, accurate diagnosis.

Safety First: Always disconnect the negative battery terminal before starting. If you’re uncomfortable with electrical testing, a professional diagnostic at a shop typically costs $75-$120.

2. System Understanding

The blower motor pushes air through your HVAC system. Its speed is controlled by the blower motor resistor, which creates different electrical paths to reduce fan speed. The resistor handles high current and heat, making it the most common failure point. In my experience, these components typically last 5-7 years under normal use. Failure points, in order of likelihood, are: the resistor, the fuse, the switch, the motor itself, or wiring.

3. Symptom-Based Diagnosis (Ordered by Frequency)

Symptom 1: Fan Works ONLY on HIGH Speed

Probability: ~60% of cases. Cause: Failed blower motor resistor. The high-speed setting bypasses the resistor entirely. Quick Test: Locate the resistor (usually in the blower housing under the passenger-side dash), unplug it, and inspect for melted plastic or burnt coils. Cost: $25-$60 for the part. Repair Time: 30-45 minutes for a DIYer.

Symptom 2: Fan Does Not Work on ANY Speed

Probability: ~25% of cases. Causes: Blown fuse, failed motor, or broken wiring. Quick Test: First, check the HVAC/Blower fuse in the interior fuse box (often 25A or 30A). If it’s good, listen for a “click” or hum from under the dash when you turn the fan on—if you hear it, the motor is likely seized. Cost: Motor: $80-$150; Fuse: $5. Repair Time: Motor replacement: 1-1.5 hours.

Symptom 3: Fan Works Intermittently on All Speeds

Probability: ~10% of cases. Causes: Failing motor (brushes wearing out) or a loose/corroded connector. Quick Test: Tap the blower motor housing lightly with a screwdriver handle while it’s supposed to be on. If it starts, the motor is failing. Cost: Motor: $80-$150. Repair Time: 1-1.5 hours.

Symptom 4: One Specific Speed (Not High) is Missing

Probability: ~5% of cases. Cause: Specific circuit failure within the resistor or a problem with the control switch. This is less common but points directly to the resistor pack. Diagnosis requires a multimeter test at the resistor connector.

4. Diagnostic Decision Tree

Follow this text-based flowchart:

Does the fan blow at all?
- NO → Check the HVAC/Blower fuse. If blown, replace it. If it blows again, you have a short circuit (likely a pinched wire or failing motor).
- YES → Does it work on ALL speeds?
  - NO, only HIGH works → Replace the blower motor resistor.
  - NO, one lower speed is out → Replace the blower motor resistor.
  - NO, it’s intermittent on all speeds → Test/replace the blower motor.
  - YES → System is currently functional; issue may be intermittent.

5. Repair vs. Replace Analysis

These components are almost always replaced, not repaired. Resistors and motors are wear items. When to DIY: If you’ve diagnosed a simple fuse or resistor swap. When to call a pro: If wiring repairs are needed or the motor is in a very difficult location. Cost Comparison: A resistor DIY is ~$60 in parts. A shop will charge $150-$250. A motor replacement at a shop can run $300-$500+, while DIY is under $200.

6. Prevention & Maintenance

Failure is often accelerated by a sluggish motor drawing excess current. Keeping the cabin air filter clean reduces strain on the blower. A warning sign is an unusual whining or grinding noise from the fan before it quits. In dusty climates, expect a shorter lifespan.

7. Real-World Repair Scenarios

2019 Honda Civic: Customer complaint: “Warm air except on high.” 15-minute diagnosis found a melted blower resistor. The cabin air filter was clogged, causing the motor to overwork. Replaced the resistor and filter. Total shop time: 45 minutes. Customer cost: $185.
2012 Mitsubishi Eclipse GT: Fan dead on all speeds. Found a blown 30A fuse. Replaced it, and it blew immediately. Further testing revealed a seized blower motor. Replaced motor and fuse. Total job time: 1.2 hours. Parts: $140 (motor).
2008 Mitsubishi Eclipse Spyder: Intermittent operation. Tapping the motor would get it going. Confirmed worn motor brushes. Motor replacement took 1.5 hours due to tight access behind the glove box.

FAQ

Q: Can a bad blower motor resistor cause no air at all?

A: Typically, no. If the resistor fails completely, the fan should still work on the HIGH setting, as that circuit bypasses it. No air at all points to the fuse, motor, switch, or power supply.

Q: Why does my blower resistor keep burning out every year?

A: This is a classic sign of a blower motor on its last legs. A motor with worn brushes draws higher amperage (amps), which overheats and destroys the resistor. The real fix is to replace the motor and the resistor together.

Q: Is it safe to drive with the blower not working?

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