Where is the blower motor relay on a 2007 trailblazer?

If the motor blows on med-high but not high or low, it's the resistor.

The fan relay is the problem. Replace it.

replace with this and it will work. Heater Blower Motor Resistor 2003 Chevrolet Trailblazer 2WD 8 Cylinders...

check to see if you have voltage to the blower motor, if you do, then replace the blower motor. If no voltage, check fuses, relay and the blower motor switch, or blower motor resistor

The relay is part of the control module. But you should first check the fuses, #35 fuse in the underhood fuse panel and #44 fuse in the rear fuse panel. Also inspect the resistor module for burn damage.

A mechanic would check for voltage at the fuse or breaker, the fan relay, the blower motor, and the resistor.

You replaced the resistor and WHAT relay? The blower motor circuit on a 2007 Dodge Nitro does not use a relay.

The blower resistor gets it's power from the A/C - heater control unit.

If you check for voltage at the blower motor resistor connector (Key on, relay disconnected), the DARK BLUE/GREY wire should be hot when the control switch is on HIGH. The DARK BLUE/VIOLET wire should be hot with the switch in the MEDIUM 2 position.The DARK BLUE/ORANGE wire should be hot with the switch in the MEDIUM 1 position. The DARK BLUE/BROWN wire should be hot with the switch on LOW.

If any of these are not as stated above, then you either have a bad A/C - heater control unit, or faulty wiring between the control unit and the resistor.

It could be the blower resistor, located usually right beside the blower, easy to replace 2 or 3 screws and 1 or 2 plugs and your done.

Your looking for the blower resistor. Its on the passenger side under the dash. Two of the wires go the the blower motor. The wire connector and the resistor can burn or corrode. The replacement is easy two screws hold the resistor in and the connector can be replace with **** connectors.

check blower motor and resistor with test light,