Test heat resister - 1997 Chevrolet Blazer

If the board is melted, you need to replace it, new or from a breakers yard.

It could be the heating element or the Driver heated seat module ! Do you know anything about automotive electronic's ? Circuit testing with a DMM - digital multi-meter ? This system has a element in the seat an the back . None work ?

• Heated Seat Inoperative

• Circuitry open/shorted.
• Damaged heated seat heater elements.
• Damaged heated seat module.
• Damaged heated seat switch.

• GO to Pinpoint Test G .

PINPOINT TEST G: HEATED SEAT INOPERATIVE G1 TEST HEATER ELEMENTS

• Disconnect connectors C352 LH ( C356 RH) at heater modules.
• Using an ohmmeter, measure resistance of heater elements according to the following chart:
  
  Connectors C352 LH; 356 RH Pin Circuit Pin Circuit 12 1067 (P/LB) 9 1066 (GY/LB)

Is resistance of elements 2.5-10 ohms?
Yes No GO to G2 . GO to G4 .
The seat heater module is under the driver seat .

G2 TEST HEAT SENSORS FOR OPEN CIRCUIT

• Using an ohmmeter, measure the resistance of sensors according to the following chart:
  
  Connectors C352 LH; 356 RH Pin Circuit Pin Circuit 11 1063 (O/LB) 10 1062 (R/LB) 6 1061 (BR/LB)

Is resistance more than 10,000 ohms?
Yes No REPLACE trim covers. RESTORE vehicle. RETEST system. GO to G3 . G3 TEST HEAT SENSORS FOR SHORT CIRCUIT

• Using an ohmmeter connected to a known good ground measure resistance of Circuit 1063 (O/LB) at Pin C352 LH; Pin C356 RH.
• Measure resistance of Circuit 1061 (BR/LB) at Pin C352 and Pin C356 .

Is resistance 0 ohms?
Yes No REPLACE trim covers. RESTORE vehicle. RETEST system. GO to G6 .
G4 TEST CIRCUITS BETWEEN HEATER MODULE AND HEATING ELEMENT CONNECTOR

• Disconnect connectors C353 and C351 LH.
• Disconnect connectors C355 and C354 RH.
• Using an ohmmeter, measure resistance of circuits between module connector and heater element connector according to the following chart:
  
  Connectors C352 LH; 356 RH Pin Circuit Pin Circuit 12 1067 (P/LB) 11 1063 (O/LB) 6 1061 (BR/LB) 10 1062 (R/LB) 9 1066 (GY/LB)

Is resistance less than 5 ohms?
Yes No GO to G5 . SERVICE suspect circuit for open. RESTORE vehicle. RETEST system.
G5 TEST HEAT ELEMENT AND SENSOR CIRCUITS FOR SHORT TO GROUND

• Refer to Circuit charts in G4.
• Using an ohmmeter connected to known good ground, check resistance of circuits.

Is resistance less than 10 K ohms?
Yes No SERVICE suspect circuit for short to ground. RESTORE vehicle. RETEST system. Circuits satisfactory. REPLACE trim cover. G6 TEST HEATED SEAT SWITCH POSITION 1

• Disconnect connector C352 LH ( C356 RH).
• Make sure switch is in position 1.
• Using an ohmmeter measure resistance between Pin C352 , Circuit 1018 (LG/O) and Pin C352 , Circuit 1019 (T/LB).
• Measure resistance between Pin C356 , Circuit 579 (BK/O) and Pin C356 , Circuit 580 (BR).

Is resistance between 2.0 K and 2.75 K ohms?
Yes No GO to G7 . GO to G14 .

You have probably burnt up the element as it is a 17 year old seat now. The elements are replaceable, but the labor is pretty spendy. To test it you will need a multimeter to check for continuity across the connectors that go to the seat heating elements and check for voltage at the car side of the connector. If you have 12v to one side of the connector and continuity to ground at the other side, and do not have continuity to the seat side between the connectors, you know it is a bad element.

Heated Seats
This system allows the electrical heating of the front seats on passenger demand.
The components of the system are:

• the seat heating elements located in the seat cushion and backrest.
• the heated seat control switch, located on the seat side trim panel.
• temperature sensors located in the seat cushion heating elements.
• heated seat relay.

Do both front seat heaters not work ? Do you know how to test electrical circuits with voltmeter ?
PINPOINT TEST J: THE HEATED SEAT IS INOPERATIVE Test Step Result / Action to Take J1 CHECK HEATED SEAT SWITCH OPERATION

• Key in ON position.
• Press the heated seat switch on the driver and passenger seats.
• Are both heated seat switch indicators illuminated?

Yes
If both indicators illuminate, Go To Pinpoint Test K . If only one indicator illuminates, GO to J5 .

No
GO to J2 . J2 CHECK THE HEATED SEAT RELAY CIRCUITS

• Key in OFF position.
• Disconnect: Heated Seat Relay C3250 (located under the driver seat).
• Key in ON position.
• Measure the voltage at heated seat relay C3250-86, circuit 1003 (GY/YE), harness side and ground; and between C3250-30, circuit 566 (DG), harness and ground.
  
• Are the voltages greater than 10 volts?

Yes
GO to J3 .

No
REPAIR inoperative 1003 (GY/YE) or 566 (DG) circuit. TEST the system for normal operation. J3 CHECK HEATED SEAT RELAY GROUND CIRCUIT

• Key in OFF position.
• Measure the resistance between heated seat relay C3250-85, circuit 57 (BK), harness side and ground.
  
• Is the resistance less than 5 ohms?

Yes
GO to J4 .

No
REPAIR circuit 57 (BK). TEST the system for normal operation. J4 CHECK THE HEATED SEAT RELAY

• Install a fused jumper lead between heated seat relay 3250-30, circuit 566 (DG), harness side and heated seat relay C3250-87, circuit 1064 (YE/LB), harness side.
  
• Do both heated seat indicators illuminate when pressed?

Yes
INSTALL a new heated seat relay. TEST the system for normal operation.

No
REPAIR circuit 1064 (YE/LB) to switches. TEST the system for normal operation. J5 CHECK INOPERATIVE HEATED SEAT SWITCH INPUT

• Key in OFF position.
• Disconnect: Heated Seat Switch C320 (Driver) or C321 (Passenger) for the inoperative heated seat.
• Key in ON position.
• Measure the voltage between heated seat switch C320-2 (driver) or C321-2 (passenger), circuit 1064 (YE/LB), harness side and ground .
  
• Is the voltage greater than 10 volts?

Yes
GO to J6 .

No
REPAIR circuit 1064 (YE/LB). TEST system for normal operation. J6 CHECK CIRCUIT 57 (BK) FOR AN OPEN

• Measure the resistance between heated seat switch C320-4 (driver) or C321-4 (passenger), circuit 57 (BK), harness side and ground.
  
• Is the resistance less than 5 ohms?

Yes
INSTALL a new heated seat switch. TEST the system for normal operation.

No
REPAIR circuit 57 (BK). TEST the system for normal operation It's not that simple , being a fuse . It's probably the relay or the heating element .
PINPOINT TEST K: SEAT DOES NOT HEAT BUT THE HEATED SEAT INDICATOR ILLUMINATES WHEN PRESSED ? Does it ?
Your best bet would be to take to a qualified repair shop .
Do

HI. I have a very thorough, step by step procedure that will help troubleshoot this issue. follow carefully, to isolate the problem, Use extreme caution when preforming this inspection procedure.



1.Check for broken wires or loose connectors around the fan circuit. Inspect connectors at the fan motor, relay, sensor or heat sensitive switch, and the Electronic Control Module (ECM)--your car’s computer control system. Also, make sure to check for a possible blown fan fuse. These are common and overlooked troublesome spots that may cause a fan to fail.


2.Run and bring the engine to warm temperature. With the engine running, use a voltage test light to check for power to the motor fan. Be extra careful and make sure to keep your hands and tools away from the belt, fan or any other engine moving parts. If voltage is reaching the fan motor, the test light should glow.


3.Turn off the engine after you see the light glow. Apply direct voltage to the fan motor from your car battery using a pair of spare wires. If the fan fails to operate, replace the fan motor. If the motor operates, your problem is in the motor connector.


4.Locate the heat-sensitive switch or heating sensor if the fan motor operates with direct voltage and the test light did not glow. You should find the sensor in the radiator, engine block, or thermostat housing.


5.Measure the resistance across the heating sensor with the multimeter. With the engine at cool temperature (engine off), it should register infinite resistance; with the engine at warm temperature (engine off), you should read low resistance. If both readings state infinite resistance install a new heating sensor, that’s the cause of your failing fan.


6.Check the action of the fan relay if the heating sensor is registering variable resistance. Your service manual should specify the power and ground wires according to color codes and the proper way to test it. If the fan relay fails the test replace it with a new one.


7.Check the connections going to the ECM after you determine the fan relay is working properly. If you find broken wires or loose connectors, make the necessary repairs. If you suspect a defective ECM take your vehicle to a service shop for a computer analysis. In most cases, the ECM is rare to be the cause of a failing fan. The above steps should take you to the root cause of your problem and help you fix the cooler fan.

HI. I have a very thorough, step by step procedure that will help troubleshoot this issue. follow carefully, to isolate the problem, Use extreme caution when preforming this inspection procedure.


Step1
Check for broken wires or loose connectors around the fan circuit. Inspect connectors at the fan motor, relay, sensor or heat sensitive switch, and the Electronic Control Module (ECM)--your car’s computer control system. Also, make sure to check for a possible blown fan fuse. These are common and overlooked troublesome spots that may cause a fan to fail.

Step2
Run and bring the engine to warm temperature. With the engine running, use a voltage test light to check for power to the motor fan. Be extra careful and make sure to keep your hands and tools away from the belt, fan or any other engine moving parts. If voltage is reaching the fan motor, the test light should glow.

Step3
Turn off the engine after you see the light glow. Apply direct voltage to the fan motor from your car battery using a pair of spare wires. If the fan fails to operate, replace the fan motor. If the motor operates, your problem is in the motor connector.

Step4
Locate the heat-sensitive switch or heating sensor if the fan motor operates with direct voltage and the test light did not glow. You should find the sensor in the radiator, engine block, or thermostat housing.

Step5
Measure the resistance across the heating sensor with the multimeter. With the engine at cool temperature (engine off), it should register infinite resistance; with the engine at warm temperature (engine off), you should read low resistance. If both readings state infinite resistance install a new heating sensor, that’s the cause of your failing fan.

Step6
Check the action of the fan relay if the heating sensor is registering variable resistance. Your service manual should specify the power and ground wires according to color codes and the proper way to test it. If the fan relay fails the test replace it with a new one.

Step7
Check the connections going to the ECM after you determine the fan relay is working properly. If you find broken wires or loose connectors, make the necessary repairs. If you suspect a defective ECM take your vehicle to a service shop for a computer analysis. In most cases, the ECM is rare to be the cause of a failing fan. The above steps should take you to the root cause of your problem and help you fix the cooler fan.

HI. Here is a step by step troubleshooting guide that will help you isolate the issue. use caution, and follow carefully.

Step1
Check for broken wires or loose connectors around the fan circuit. Inspect connectors at the fan motor, relay, sensor or heat sensitive switch, and the Electronic Control Module (ECM)--your car’s computer control system. Also, make sure to check for a possible blown fan fuse. These are common and overlooked troublesome spots that may cause a fan to fail.
Step2
Run and bring the engine to warm temperature. With the engine running, use a voltage test light to check for power to the motor fan. Be extra careful and make sure to keep your hands and tools away from the belt, fan or any other engine moving parts. If voltage is reaching the fan motor, the test light should glow.
Step3
Turn off the engine after you see the light glow. Apply direct voltage to the fan motor from your car battery using a pair of spare wires. If the fan fails to operate, replace the fan motor. If the motor operates, your problem is in the motor connector.
Step4
Locate the heat-sensitive switch or heating sensor if the fan motor operates with direct voltage and the test light did not glow. You should find the sensor in the radiator, engine block, or thermostat housing.
Step5
Measure the resistance across the heating sensor with the multimeter. With the engine at cool temperature (engine off), it should register infinite resistance; with the engine at warm temperature (engine off), you should read low resistance. If both readings state infinite resistance install a new heating sensor, that’s the cause of your failing fan.
Step6
Check the action of the fan relay if the heating sensor is registering variable resistance. Your service manual should specify the power and ground wires according to color codes and the proper way to test it. If the fan relay fails the test replace it with a new one.
Step7
Check the connections going to the ECM after you determine the fan relay is working properly. If you find broken wires or loose connectors, make the necessary repairs. If you suspect a defective ECM take your vehicle to a service shop for a computer analysis. In most cases, the ECM is rare to be the cause of a failing fan. The above steps should take you to the root cause of your problem and help you fix the cooler fan.

Use this thorough testing procedure to troubleshoot this issue.

Step1
Check for broken wires or loose connectors around the fan circuit. Inspect connectors at the fan motor, relay, sensor or heat sensitive switch, and the Electronic Control Module (ECM)--your car’s computer control system. Also, make sure to check for a possible blown fan fuse. These are common and overlooked troublesome spots that may cause a fan to fail.
Step2
Run and bring the engine to warm temperature. With the engine running, use a voltage test light to check for power to the motor fan. Be extra careful and make sure to keep your hands and tools away from the belt, fan or any other engine moving parts. If voltage is reaching the fan motor, the test light should glow.
Step3
Turn off the engine after you see the light glow. Apply direct voltage to the fan motor from your car battery using a pair of spare wires. If the fan fails to operate, replace the fan motor. If the motor operates, your problem is in the motor connector.
Step4
Locate the heat-sensitive switch or heating sensor if the fan motor operates with direct voltage and the test light did not glow. You should find the sensor in the radiator, engine block, or thermostat housing.
Step5
Measure the resistance across the heating sensor with the multimeter. With the engine at cool temperature (engine off), it should register infinite resistance; with the engine at warm temperature (engine off), you should read low resistance. If both readings state infinite resistance install a new heating sensor, that’s the cause of your failing fan.
Step6
Check the action of the fan relay if the heating sensor is registering variable resistance. Your service manual should specify the power and ground wires according to color codes and the proper way to test it. If the fan relay fails the test replace it with a new one.
Step7
Check the connections going to the ECM after you determine the fan relay is working properly. If you find broken wires or loose connectors, make the necessary repairs. If you suspect a defective ECM take your vehicle to a service shop for a computer analysis. In most cases, the ECM is rare to be the cause of a failing fan. The above steps should take you to the root cause of your problem and help you fix the cooler fan.

HI. I have prepared some steps for you to follow.This will aid you will the troubleshooting.


Step1 Check for broken wires or loose connectors around the fan circuit. Inspect connectors at the fan motor, relay, sensor or heat sensitive switch, and the Electronic Control Module (ECM)--your car’s computer control system. Also, make sure to check for a possible blown fan fuse. These are common and overlooked troublesome spots that may cause a fan to fail. Step2 Run and bring the engine to warm temperature. With the engine running, use a voltage test light to check for power to the motor fan. Be extra careful and make sure to keep your hands and tools away from the belt, fan or any other engine moving parts. If voltage is reaching the fan motor, the test light should glow. Step3 Turn off the engine after you see the light glow. Apply direct voltage to the fan motor from your car battery using a pair of spare wires. If the fan fails to operate, replace the fan motor. If the motor operates, your problem is in the motor connector. Step4 Locate the heat-sensitive switch or heating sensor if the fan motor operates with direct voltage and the test light did not glow. You should find the sensor in the radiator, engine block, or thermostat housing. Step5 Measure the resistance across the heating sensor with the multimeter. With the engine at cool temperature (engine off), it should register infinite resistance; with the engine at warm temperature (engine off), you should read low resistance. If both readings state infinite resistance install a new heating sensor, that’s the cause of your failing fan. Step6 Check the action of the fan relay if the heating sensor is registering variable resistance. Your service manual should specify the power and ground wires according to color codes and the proper way to test it. If the fan relay fails the test replace it with a new one. Step7 Check the connections going to the ECM after you determine the fan relay is working properly. If you find broken wires or loose connectors, make the necessary repairs. If you suspect a defective ECM take your vehicle to a service shop for a computer analysis. In most cases, the ECM is rare to be the cause of a failing fan. The above steps should take you to the root cause of your problem and help you fix the cooler fan.

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The Engine Coolant Temperature (ECT) sensor is mounted in the intake manifold and sends engine temperature information to the ECM. The ECM supplies 5 volts to the coolant temperature sensor circuit. The sensor is a thermistor which changes internal resistance as temperature changes. When the sensor is cold (internal resistance high), the ECM monitors a high signal voltage which it interprets as a cold engine. As the sensor warms (internal resistance low), the ECM monitors a low signal voltage which it interprets as warm engine.
Fig. 1: View of the Engine Coolant Temperature (ECT) sensor Fig. 2: Engine Coolant Temperature (ECT) sensor locationTESTING
See Figures 3 and 4

1. Remove the ECT sensor from the vehicle.
2. Immerse the tip of the sensor in container of water.
3. Connect a digital ohmmeter to the two terminals of the sensor.
4. Using a calibrated thermometer, compare the resistance of the sensor to the temperature of the water. Refer to the engine coolant sensor temperature vs. resistance illustration.
5. Repeat the test at two other temperature points, heating or cooling the water as necessary.
6. If the sensor does not meet specification, it must be replaced.

Fig. 3: Intake Air Temperature (IAT) and Engine Coolant Temperature (ECT) sensor wiring diagram Fig. 4: ECT sensor temperature vs. resistance values