2003 pontiac grand prix heater blower problem sometimes it comes on and sometimes not. it has 5 speeds and it will work in various speeds and then not

check the blower motor (under right side of dash)for a loose connection.

When blower is running wiggle the switch knob in an effort to check for a loose connection in the control panel.

sounds like a bad connection, with fan on wiggle the wires comming out of motor, also wiggle the wires at the resistor, it's next to motor.
when you get to a point where the motor stops, that's where the loose connection is.
remove connector and insp. terms.

GM Service Bulletin No.: 05-01-39-001A

Subject:
Blower Motor Inoperative or Intermittent, Blower Speed May Drop or Blower Continues to Run After Key Off (Install a Capacitor at Blower Motor Control Module Connector)

Models:2004-2005 Pontiac Grand Prix

Condition
Some customers may comment on an inoperative or intermittent Heating, Ventilation and Air Conditioning (HVAC) blower motor. Others may comment that the blower motor speed may momentarily drop or that the blower motor continues to run after the key is turned off.

Cause
This condition may be caused by a voltage spike from the wiper motor. The voltage spike may cause a logic lock up in the blower motor control module that may be either momentary or permanent.

Correction
Install a capacitor at the blower control module connector.
DO NOT replace the blower control module, blower motor or the HVAC Control Head.
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good call, i missed that bulletin, check to see if it applys, if so kool, if not let us know, we can walk you thru the daig.

Keep in mind that these bulletins are not a diagnosis of the problems you are having so don't buy any parts until the cause of the problem has been found and verified. (save money and time)

check ground, drop a line of chassis to bolt holdin motor it and see if prob continues

the motor is grounded by a wire in the wiring harness. If you suspect that the ground is the problem, check the ground wire (black) with an ohmmeter connected to the ground wire and to a good chassis/frame ground. Meter should read 0.00