* Blown Fuse: This is the easiest and cheapest fix. Check your owner's manual to locate the fuse for the blower motor and verify its integrity. A blown fuse will completely stop the fan or severely limit its output.
* Blower Motor Resistor: This component controls the fan speeds. A failing resistor often results in only the highest speed (if any) working, or weak airflow on all speeds. It's a relatively inexpensive part to replace, but access can vary depending on the year of your Rendezvous.
* Blower Motor: The motor itself might be failing. This is a more expensive repair than the resistor, requiring motor replacement. A failing motor might produce a weak, whining, or grinding noise.
* Loose or Damaged Blower Motor Connections: Check the electrical connections to the blower motor for corrosion, looseness, or damage. A poor connection prevents the motor from receiving sufficient power.
* Debris in the Blower Housing: Leaves, debris, or even small toys can obstruct the airflow through the blower housing, reducing the amount of air coming out of the vents. This usually manifests as reduced airflow across all speeds and isn't specific to heating or cooling.
* HVAC Control Module (or blend door actuator): While less likely to cause *only* weak airflow, a problem with the HVAC control module or a blend door actuator could affect fan speed or airflow distribution, potentially causing weaker than expected output. These are more complex issues and require more specialized diagnostic tools.
Troubleshooting Steps:
1. Check the fuses first! This is the simplest and quickest check.
2. Listen carefully to the blower motor: Is it making unusual noises? A grinding or whining sound suggests a failing motor.
3. Inspect the blower motor resistor (if you can access it easily). Look for obvious signs of damage or burning.
4. Check all electrical connections to the blower motor. Clean any corroded connections.
5. Check for blockages in the vents or blower housing (if accessible).
If you're not comfortable performing these checks yourself, it's best to take your Rendezvous to a qualified mechanic or auto electrician for diagnosis and repair. They have the tools and expertise to pinpoint the exact cause and fix the problem efficiently. Remember to specify that the fan blows weakly on *all* speeds to help them narrow down the possibilities.
