FAQ
TL;DR: On a 2004 Grand Vitara 2.0 diesel with 8 blower speeds, a failed blower resistor was the root cause; “resistor was damaged.” [Elektroda, sadek1979, post #16924054]
Why it matters: This FAQ helps DIYers quickly confirm power, relay control, and the resistor so cabin airflow is restored.
Quick Facts
- Vehicle: Suzuki Grand Vitara 2004, 2.0 diesel; HVAC has 8 selectable blower speeds. [Elektroda, sadek1979, post #16922372]
- Symptom seen: only speeds 7–8 worked until the resistor was replaced. [Elektroda, sadek1979, post #16922372]
- Fix that solved the thread: replace the blower resistor; speeds returned after swap. [Elektroda, sadek1979, post #16924054]
- Blower relay control wire noted as green/yellow near passenger-side blower. [Elektroda, sadek1979, post #16922372]
- Fuse 43 checked OK; jumper across the relay did not spin the fan. [Elektroda, sadek1979, post #16902419]
How do I diagnose no airflow on a 2004 Grand Vitara 2.0 diesel?
Verify Fuse 43, then check for power and ground at the blower and resistor. Inspect the passenger-side blower relay and the green/yellow relay control wire. If the relay clicks only when externally powered and speeds 7–8 work, suspect the blower resistor module. Finish by confirming the HVAC panel sends a varying control signal to the resistor. [Elektroda, sadek1979, post #16922372]
Where is the blower relay and what wire controls it?
The blower relay sits on the passenger side near the blower housing. The relay’s control is on a green/yellow wire. When you feed that control wire, the relay engages and the fan can run, confirming the downstream circuit. Lack of control voltage indicates an upstream issue in panel output or wiring. [Elektroda, sadek1979, post #16922372]
Why do only high blower speeds work?
When only speeds 7–8 operate, the resistor pack or its control path is compromised. In the thread case, replacing the resistor restored all eight speeds. Quote: “Resistor was damaged.” That points to a failed resistor transistor or thermal fuse inside the module. [Elektroda, sadek1979, post #16924054]
What voltage should the HVAC panel send to the blower resistor?
The panel outputs a varying control voltage as you select speeds; recorded values ranged from about 4 V at speed 1 up to roughly 14 V at speed 8. If those values do not change at the resistor connector, the resistor or the panel/wiring is at fault. [Elektroda, sadek1979, post #16922372]
How do I test the blower resistor quickly?
Use a multimeter on the thin control wire at the resistor. Turn the speed knob and watch for changing voltage. If you see a stable value or no change, swap in a known-good resistor and retest. A restored gradient confirms a failed resistor module. [Elektroda, szymitsu21, post #16922376]
Can I bypass the relay to see if the fan runs?
Jumpering the relay power contacts may not spin the fan if the control side is missing. In the thread, adding control voltage to the green/yellow pin clicked the relay and the blower ran, proving the motor and power path were intact. [Elektroda, sadek1979, post #16922372]
What does the second thin wire to the resistor do?
One thin wire carries the variable speed-control signal. The other thin wire can relate to A/C logic, enabling the blower signal that allows compressor engagement when the fan is on. This ties blower operation to A/C permissives. [Elektroda, Raywood, post #16923595]
Is the climate control panel a common failure for no blower speeds?
Panel output was suspected when no variable voltage appeared at the resistor. However, replacing the resistor restored proper voltage change and speeds. Confirm panel output at the resistor before condemning the panel to avoid unnecessary replacement. [Elektroda, sadek1979, post #16924054]
What basic tools do I need for this diagnosis?
Use a digital multimeter, back-probing leads, and access to the passenger kick panel. Optional: a fused jumper wire to test the relay control on the green/yellow lead. These tools verified power, control voltage, and relay function in the thread. [Elektroda, sadek1979, post #16922372]
What is Webasto, and does it affect the blower issue here?
Webasto is an auxiliary heater brand. The user checked for its presence; none was installed. It did not factor into the diagnosis or fix for the blower on this vehicle. [Elektroda, T5, post #16902546]
My blower shows neither voltage nor ground at the motor. What next?
Confirm Fuse 43 continuity and inspect grounds. Then test the relay: ensure the control side receives voltage on the green/yellow wire. If applying control voltage makes the blower run, troubleshoot the control signal path and the resistor module. [Elektroda, sadek1979, post #16902419]
How do I verify a resistor fault in three steps?
- Back-probe the thin control wire at the resistor and rotate the fan-speed knob.
- Look for voltage changing from low (≈4 V) to high (≈14 V) across speeds.
- If no change, install a known-good resistor; recheck for restored speed steps. [Elektroda, sadek1979, post #16922372]
Could a stiff or failing blower motor cause speed loss?
Yes. A dragging motor increases current and can overheat the resistor module, accelerating failure. In the thread, the original fan “went hard,” and replacing the fan and the resistor restored correct operation. This is an edge case worth checking early. [Elektroda, sadek1979, post #16922372]
What if the relay has power but jumping it does nothing?
If a jumper across power contacts fails, confirm the motor ground and the control side. In the reported case, the relay had power, but only adding control voltage engaged it and ran the blower. That pointed upstream to the resistor control circuit. [Elektroda, sadek1979, post #16902419]
Do wiring checks between the panel and resistor matter?
Yes. The user verified both thin wires from the panel to the resistor had continuity and no shorts. This isolated the failure to the resistor module rather than the harness. Always confirm wiring before replacing control units. [Elektroda, sadek1979, post #16922372]
