QuestionQUESTION: where does the heater motor in my grand prix get its main power from? there is a regulator with a red,black and small grey wire going into it and then a black and purple wire coming from it to the blower motor, all of these wires are dead yet the fuses and relays are fine. any ideas?
ANSWER: Hi Mike:
This is a simple yet complex system for the blower motor. you should have power and ground to that blower motor control module red being battery power and glack being the ground. the grey wire is a signal from the HVAC control head in the dash. That wire is pulse width modulated so unless you have a computer frienldy LED test light or a volt meter you will not measure anything on that wire. The wires out of that the purple and black wires for the motor are controlled by the module for the motor. I think on this that it has constant power but that module controls the ground which is the black wire. My best guess is that module is bad I know you said the wires going to it are dead but Check them again use a test light across the black and red wires going into the module. If the light lights it's the module. I have never changed a HVAC control head on one of thse cars for this issue. But ther is always a first time.. Good luck and happy holidays :}
---------- FOLLOW-UP ----------
QUESTION: thanks todd. I tested the wires again going into the module but they have no power at all comming in or going out, that is why i am questioning where the main power is coming from.is there anywhere online that i can find a wiring diagram for this car?
AnswerHi Mike:
No there is no place for you to see the stuff on the internet It's strictly dealership information. But depending on what engine this has that module gets it power from fuse labeled Batt 4 or batt main 4 both of them are under the hood in that fuse box.
Blower Motor Inoperative
Step
Action
Value(s)
Yes
No
Schematic Reference: HVAC Schematics
Connector End View Reference: HVAC Connector End Views
DEFINITION: The blower motor is inoperative in all speed positions.
1
Did you perform the Diagnostic System Check - Vehicle?
--
Go to Step 2
Go to Diagnostic System Check - Vehicle
2
Turn ON the ignition, with the engine OFF.
Place the blower switch in each speed position.
Does the blower motor operate in any of the speed positions?
--
Go to Blower Motor Malfunction
Go to Step 3
3
Turn OFF the ignition.
Disconnect the blower motor connector.
Turn ON the ignition, with the engine OFF.
Connect a test lamp between the blower motor supply voltage circuit and the blower motor control circuit.
Place the blower motor switch in the minimum speed position.
Does the test lamp illuminate?
--
Go to Step 9
Go to Step 4
4
Test the battery positive voltage circuit of the blower motor control processor for the following:
• An open
• A high resistance
• A short to ground
Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?
--
Go to Step 15
Go to Step 5
5
Test the ground circuit of the blower motor control processor for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?
--
Go to Step 15
Go to Step 6
6
Important: Ensure that the blower motor control processor connector and the HVAC control module connectors are connected during this step in order to avoid misdiagnosis.
Measure the voltage from the blower motor speed control circuit at the HVAC control module to a good ground.
With the ignition ON, turn the blower motor to high then to OFF.
Does the voltage measure near the specified values?
5 V OFF
1 V ON
Go to Step 10
Go to Step 7
7
Turn OFF the ignition.
Disconnect the HVAC control module.
Turn ON the ignition, with the engine OFF.
Measure the voltage from the blower motor speed control circuit of the HVAC control module to a good ground.
Does the voltage measure near the specified value?
5 V
Go to Step 11
Go to Step 8
8
Test the blower motor speed control circuit of the HVAC control module for the following:
• An open
• A short to ground
• A short to voltage
Refer to Circuit Testing and Wiring Repairs .
Did you find and correct the condition?
Go to Step 15
Go to Step 10
9
Inspect for poor connections at the harness connector of the blower motor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?
--
Go to Step 15
Go to Step 12
10
Inspect for poor connections at the harness connector of the blower motor control processor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?
--
Go to Step 15
Go to Step 13
11
Inspect for poor connections at the harness connector of the HVAC control module . Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .
Did you find and correct the condition?
--
Go to Step 15
Go to Step 14
12
Replace the blower motor. Refer to Blower Motor Replacement .
Did you complete the replacement?
--
Go to Step 15
--
13
Replace the blower motor control processor. Refer to Blower Motor Control Module Replacement .
Did you complete the replacement?
--
Go to Step 15
--
14
Replace the HVAC control module. Refer to Control Module References for replacement, setup, and programming.
Did you complete the replacement?
--
Go to Step 15
--
15
Operate the system in order to verify the repair.
Did you correct the condition?
I just cut and pasted the diagnosis from our web site into this reply It's all chopped up because of the intenet explorer format but you can get the Idea as to what they are looking for The info is actually in a 5 line chart I don't know if it's going to look good when you print this out or not but give it a try. Good luck :)
