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Ask -Brad- Your Own Question
-Brad-
-Brad-, Dodge Dealership Tech
Category: Dodge
Satisfied Customers: 7380
Experience:  16 Yrs Chrysler/Dodge Technician. ASE Master Certified(L-1)
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Have a 2001 Dodge Ram 3500. Heated seats are not working.

Customer Question

Have a 2001 Dodge Ram 3500. Heated seats are not working. Switch lights come on but seat do not heat. A few times the light blinked on the drivers side but they both light on high and low now
Submitted: 1 year ago.
Category: Dodge
Expert:  -Brad- replied 1 year ago.

It would be best to see what codes it has but here is the diag to check the seat.

DIAGNOSIS & TESTING - HEATED SEAT ELEMENT AND SENSOR

The heated seat module will self-diagnose shorted or open heated seat element circuits and the sensor circuits. Refer to Heated Seat System in this section for the location of the proper heated seat system diagnosis and testing procedures. To manually check the heated seat element and sensor circuits, proceed as follows. The wire harness connectors for the seat cushion heated seat element and sensor and for the seat back heated seat element are located under the seat, near the rear edge of the seat cushion frame. Refer to Wiring Diagrams for the location of complete heated seat system wiring diagrams.

HEATED SEAT ELEMENT

  1. Disconnect and isolate the battery negative cable. Disconnect the 4-way heated seat wire harness connector. Check for continuity between the two heated seat element circuit cavities in the seat cushion trim cover half of the 4-way heated seat wire harness connector. There should be continuity. If OK, go to Step 2. If not OK, go to Step 3.
  2. Check for continuity between one of the heated seat element circuit cavities in the seat cushion trim cover half of the 4-way heated seat wire harness connector and the seat cushion frame. There should be no continuity. If OK, go to Step 5. If not OK, go to Step 4.
  3. Disconnect the 2-way heated seat wire harness connector between the seat cushion trim cover and the seat back trim cover. Check for continuity between the heated seat element circuit cavity and the ground circuit cavity in the seat back trim cover half of the 2-way heated seat wire harness connector. There should be continuity. If OK, go to Step 5. If not OK, replace the faulty seat back trim cover unit.
  4. Check for continuity between the heated seat element circuit cavity in the seat back trim cover half of the 2-way heated seat wire harness connector and the seat back frame. There should be no continuity. If OK, go to Step 5. If not OK, replace the faulty seat back trim cover unit.
  5. Test the seat wire harness between the heated seat module connector and the 4-way heated seat wire harness connectors for shorted or open circuits. If OK, replace the faulty seat cushion trim cover unit. If not OK, repair the shorted or open seat wire harness as required.

HEATED SEAT SENSOR

  1. Disconnect and isolate the battery negative cable. Disconnect the 4-way heated seat wire harness connector. Using an ohmmeter, check the resistance between the heated seat sensor input circuit cavity and the heated seat sensor feed circuit cavity in the seat cushion cover half of the 4-way heated seat wire harness connector. The heated seat sensor resistance should be between 1 kilohm and 200 kilohms. If OK, go to Step 2. If not OK, replace the faulty seat cushion trim cover unit.
  2. Test the seat wire harness between the heated seat module connector and the 4-way heated seat wire harness connector for shorted or open circuits. If OK, refer to Heated Seat Module in Electronic Control Modules for the location of the proper heated seat module diagnosis and testing procedures. Also refer to the Body Diagnostic Manual for additional diagnosis and testing procedures. If not OK, repair the shorted or open heated seat wire harness as required.
Expert:  -Brad- replied 1 year ago.

Thank you for the positive rating.

Brad

Expert:  -Brad- replied 1 year ago.

Don't forget to rate so I'm compensated for my time..Don't forget to rate so I'm compensated for my time..

Expert:  -Brad- replied 1 year ago.

Don't forget to rate so I'm compensated for my time..

Customer: replied 1 year ago.
Have been tied up. Will take out the meter today and test things
Expert:  -Brad- replied 1 year ago.

That will be fine.. Follow up questions are free of charge after the rating.

Have a greatday,

Brad

Customer: replied 1 year ago.
Tested wires going to seat covers. Appear to be good. I kept the plug unplugged from the harness and turned on the switch which flashed on the high mode. I reconnected the harness and the light stayed on like it is suppose to but still no heat. Opened up the heated seat module and did not see any burnt parts.
Customer: replied 1 year ago.
Months ago around when the seats stopped working the radio fuse blew. There was as short. When I attempted to find the short by disassembling the dash and overhead console, unfortunately it cleared itself. So I did not find the problem. I am also having problems with my antilock brakes. The front left wheel sensor is erroring out but have changed the sensor. Still no good. Don't know if this could all be related.
Expert:  -Brad- replied 1 year ago.

It's likely you have a bad heated seat pad.. You would need to disassemble the seat to inspect the pad for burnt parts.

Customer: replied 1 year ago.
But I didn't get an open reading with the ohm meter or a short. I even checked for a short to ground which was negative
Expert:  -Brad- replied 1 year ago.

Can you watch the flashing lights and determine what your issue is?

Customer: replied 1 year ago.
The lights on the switch work as they should and do not flash. So reading the document it looks like it could be the heated seat module. I took it apart and did not see anything burnt but that does not mean anything. Is there a way to check this module?
Expert:  -Brad- replied 1 year ago.

You will need a scantool such as the DRBIII we use here at the dealership to determine if it's a bad module..

Expert:  -Brad- replied 1 year ago.

DIAGNOSIS AND TESTING - SEAT HEAT INTERFACE MODULE

If a heated seat fails to heat and one or both of the indicator lamps on a heated seat switch flash, refer to Heated Seat System Diagnosis and Testing in Heated Systems for flashing LED failure identification. Refer to Wiring Diagrams in for complete heated seat system wiring diagrams.

  1. Remove the heated seat module from its mounting location

    NOTE: IN ORDER TO PERFORM THE FOLLOWING TESTS IT WILL BE NECESSARY TO REMOVE THE HEATED SEAT RELAY AND INSTALL A JUMPER WIRE IN TERMINALS 87 AND 30, BYPASSING THE HEATED SEAT RELAY.

    NOTE: ANY RESISTANCE VALUES (OHMS Ω) GIVEN IN THE FOLLOWING TEXT ARE SUPPLIED USING THE AUTOMATIC RANGE GENERATED BY A FLUKE® AUTOMOTIVE METER. IF ANOTHER TYPE OF MEASURING DEVICE IS USED THE VALUES GENERATED MAY NOT BE THE SAME AS THE RESULTS SHOWN HERE, OR MAY HAVE TO BE CONVERTED TO THE RANGE USED HERE.

RIGHT SEAT HEATER INOPERATIVE

  1. If a heated seat heats but one or both indicator lamps (LED's) on the heated seat switch fail to illuminate, check the driver circuit with the inoperative LED for a short to ground. If OK, replace the heated seat switch. If NOT OK repair the short to ground as required and than replace the heated seat switch.

    NOTE: IF THE RIGHT SEAT CUSHION IS ALREADY WARM THE FOLLOWING STEP WILL NOT PROVE CONCLUSIVE.

  2. Back-probe the heated seat module wire harness connector , do not disconnect. Check cavity #3 for battery voltage when the right heated seat switch is turned “ON”, voltage should be present, If OK go to Step 3 If NOT OK, test the right heated seat switch . If the switch tests OK, check for continuity between the switch and control module on the MUX circuit, If OK replace the heated seat control module. If NOT OK, repair the open or shorted MUX circuit as required.

    NOTE: BE CERTAIN THE BATTERY IS FULLY CHARGED BEFORE TESTING. FAILURE TO DO SO CAN RESULT IN INCORRECT READINGS.

  3. Back-probe the heated seat module wire harness connector , do not disconnect. Check cavity #10 for battery voltage, while observing the voltmeter depress the right heated seat switch low setting twice, voltage should toggle between approx.12v and 8v, If OK go to Step 4. If NOT OK check for continuity between the switch and control module on the low heat driver circuit, If OK replace the heated seat control module.
  4. Back-probe the heated seat module wire harness connector , do not disconnect. Check cavity #11 for battery voltage, while observing the voltmeter depress the right heated seat switch high setting twice, voltage should toggle between approx.12v and 8v, If OK go to Step 5. If NOT OK check for continuity between the switch and control module on the high heat driver circuit, If OK replace the heated seat control module.
  5. Back-probe the heated seat module wire harness connector , do not disconnect. Check cavity #2 for approx. 5v, voltage should be present, If OK go to Step 6. If NOT OK replace the heated seat control module.
  6. Back-probe the heated seat module wire harness connector, do not disconnect. Check cavity #7 for a range in voltage from 1.72v (warm seat) – 3.0v (cold seat). It should be within this range, If OK replace the heated seat module. If NOT OK test the Heated Seat Sensor. If NOT OK, replace the right heated seat element and sensor assembly. If the heated seat sensor tests OK, check for continuity between the right heated seat cushion connector and control module connector on the 5v supply circuit, If NOT OK, repair the open or shorted 5v supply circuit as required. If OK check for continuity between the right heated seat cushion connector and control module connector on the temperature sensor input circuit. If NOT OK, repair the open or shorted temperature sensor input circuit as required. If OK replace the heated seat control module.

LEFT SEAT HEATER INOPERATIVE

  1. If a heated seat heats but one or both indicator lamps (LED's) on the heated seat switch fail to illuminate, check the driver circuit with the inoperative LED for a short to ground. If OK, replace the heated seat switch. If NOT OK repair the short to ground as required and than replace the heated seat switch.

    NOTE: IF THE LEFT SEAT CUSHION IS ALREADY WARM THE FOLLOWING STEP WILL NOT PROVE CONCLUSIVE.

  2. Back-probe the heated seat module wire harness connector , do not disconnect. Check cavity #5 for battery voltage when the left heated seat switch is turned “ON”, voltage should be present, If OK go to Step 3 If NOT OK, test the left heated seat switch . If the switch tests OK, check for continuity between the switch and control module on the MUX circuit, If OK replace the heated seat control module. If NOT OK, repair the open or shorted MUX circuit as required.
  3. Back-probe the heated seat module wire harness connector , do not disconnect. Check cavity #12 for battery voltage, while observing the voltmeter depress the left heated seat switch low setting twice, voltage should toggle between approx.12v and 8v, If OK go to Step 4. If NOT OK check for continuity between the switch and control module on the low heat driver circuit, If OK replace the heated seat control module.
  4. Back-probe the heated seat module wire harness connector , do not disconnect. Check cavity #14 for battery voltage, while observing the voltmeter depress the left heated seat switch high setting twice, voltage should toggle between approx.12v and 8v, If OK go to Step 5. If NOT OK check for continuity between the switch and control module on the high heat driver circuit, If OK replace the heated seat control module.
  5. Back-probe the heated seat module wire harness connector , do not disconnect. Check cavity #2 for approx. 5v, 5 voltage should be present, If OK go to Step 6. If NOT OK replace the heated seat control module.
  6. Back-probe the heated seat module wire harness connector, do not disconnect. Check cavity #8 for a range in voltage from 1.72v (warm seat) – 3.0v (cold seat). It should be within this range, If OK replace the heated seat control module. If NOT OK, test the Heated Seat Sensor. If NOT OK, replace the left heated seat element and sensor assembly. If the heated seat sensor tests OK, check for continuity between the left heated seat cushion connector and control module connector on the 5v supply circuit, If NOT OK, repair the open or shorted 5v supply circuit as required. If OK check for continuity between the left heated seat cushion connector and control module connector on the temperature sensor input circuit. If NOT OK, repair the open or shorted temperature sensor input circuit as required. If OK replace the heated seat control module.

BOTH SEATS INOPERATIVE

If both seats (driver and passenger) fail to heat and the indicator lamps on the heated seat switches for both seats fail to operate, test the heated seat relay and/or fuses. Refer to Relay Diagnosis and Testing in the Power Distribution section for heated seat relay diagnosis and testing procedures. If the heated seat relay checks OK, go to Step 1.

  1. Back-probe the heated seat module wire harness connector , do not disconnect. Check for continuity between the ground circuit cavity #13 of the heated seat module connector and a good ground. If OK go to Step 2. If NOT OK, repair the open or shorted ground circuit as required.
  1. Back-probe the heated seat module wire harness connector , do not disconnect. Check cavity #4 and #6 for battery voltage, voltage should be present, If OK go to Step 3. If NOT OK repair the open or shorted fused B(+) circuit as required.
  2. Back-probe the heated seat module wire harness connector, do not disconnect. Check cavity #2 for approx. 5v, voltage should be present, replace the heated seat control module with a known good module and verify system operation.