B1935 on 2007-2014 Chevrolet Tahoe: Heated Seat Fault Causes and Fixes

What's Unique About the 2007-2014 Chevrolet TAHOE

The confusion between heated seats and airbags for this code is a key issue on this platform. The wiring for both the heated seats and the airbag's Passenger Presence System (PPS) are routed together under the passenger seat. A common failure point is the wiring getting chafed, pinched, or cut by the seat's own movement on its rails, which can trigger the B1935 code and sometimes also a 'Service Air Bag' warning light, even if the primary fault is just the heated seat. Additionally, models with heated/cooled seats (like LTZ trims) are prone to the main connector on the control module overheating and melting due to high current draw, which can also set this code.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Heated seat turns on, then shuts off after approximately 30 seconds
• Heated seat indicator light stays on, but the seat produces no heat
• Heated seat does not work at all
• Heated seat indicator lights turn on for a few seconds, then turn off
• A 'Service Air Bag' message may appear on the dash information center, due to the proximity of heated seat and airbag wiring
• A visible burn mark may be found on the heating element pad once the seat cover is removed.

Most Likely Causes

1. Broken Seat Heater Element 🔴 High Probability The heating element grid is made of fine wires embedded in the seat cushion or backrest. Over time, the pressure of entering, exiting, and sitting in the seat can cause these wires to fatigue and break, creating an open circuit. The seat back element is also a very common failure point.
   How to confirm: Disconnect the heater element connector under the seat and measure the resistance across its terminals with a multimeter. A reading of infinite resistance (OL) confirms a broken element. A normal element should read approximately 6-8 ohms. Wiggling the cushion while testing can expose an intermittent break.
   Typical fix: Replace the faulty seat heater element. This requires removing the seat upholstery (hog rings) 🎬 See this walkthrough on diagnosing and repairing a broken element. to access and install the new element pad. Some owners successfully solder the broken wire as a temporary fix.
   Est. part cost: $80-$250
2. Damaged Under-Seat Wiring Harness 🟡 Medium Probability As noted in TSB #PIT5215A, the wiring harness under the seat is susceptible to damage. The seat's movement on its tracks can pinch, chafe, or sever wires, leading to a short or open circuit. This is a frequently discussed issue in owner forums.
   How to confirm: Perform a thorough visual inspection of all wiring harnesses under the affected seat. Move the seat to its forwardmost and rearmost positions to expose all wiring. Look for any signs of damage, stretched wires, or loose connectors. Pay close attention to the ground point G301 under the passenger seat.
   Typical fix: Repair the damaged section of the wire using solder and heat shrink tubing or quality butt connectors. If the connector is damaged, a new pigtail connector may be required. Ensure the repaired harness is properly routed and secured with zip ties away from any moving parts.
   Est. part cost: $5-$50
3. Burnt Connector on Heated Seat Module 🟡 Medium Probability On models with heated/cooled seats, the main 12-pin connector on the control module (under the passenger seat) is known to overheat. GM used a single power and single ground pin, which are undersized for the current draw, causing them to melt the connector housing and create a poor connection.
   How to confirm: Visually inspect the large connector plugged into the silver module under the front passenger seat. Look for melted plastic, charring, or discoloration, especially on the corner pins (typically a large pink/white power wire and a large black ground wire).
   Typical fix: Replace the burnt connector with a new pigtail. A widely cited repair is to use a Ford Motorcraft WPT-928 pigtail, which is identical. For a more robust repair, technicians often splice the single power and ground wires to feed into the two power and two ground terminals available on the module, distributing the electrical load. 🎬 Watch: How to fix the melted module connector and wiring.
   Est. part cost: $25-$55
4. Faulty Heated Seat Control Module ⚪ Low Probability
   How to confirm: This is typically diagnosed by exclusion. If the heater element, wiring, and connector have all been tested and confirmed to be good, but the fault persists, the module is the next logical suspect. A professional scan tool can often communicate with the module to check its status or perform a functional test.
   Typical fix: Replace the Heated Seat Control Module, which is located under the front passenger seat and typically held by two 10mm bolts.
   Est. part cost: $70-$150

Rare But Worth Checking

• Reversed Heater Element Connectors:

Diagnosis Steps

1. Verify the symptom: Confirm that the heated seat indicator turns on but the seat does not heat up, or turns off quickly.
2. Scan for Codes: Use an OBD-II scanner capable of reading Body (B) codes to confirm B1935 is present. Note any symptom bytes, like '0E', which TSB PIT5215A specifically links to this issue.
3. Check Fuses: Check the fuses for the heated seats (often labeled HVAC/ECAS or similar) in the instrument panel and under-hood fuse blocks.
4. Inspect Module Connector: Move the passenger seat all the way up and forward. Visually inspect the large 12-pin connector on the silver heated seat module for any signs of melting, charring, or discoloration. This is a very common failure point.
5. Inspect Under-Seat Wiring: Thoroughly inspect all wiring harnesses under both front seats for visible damage, chafing, or broken wires, paying close attention to where the harness might interact with the seat rails.
6. Test the Heater Element: Locate the connector for the seat cushion and backrest heater elements. Disconnect them and use a multimeter to measure resistance. An open loop (OL) indicates a broken element. A good element should have a low resistance, typically 6-8 ohms.
7. Test for Power and Ground: If the elements and wiring appear good, check for power and ground at the heated seat module connector. The module controls temperature by providing a PWM ground signal. A professional scan tool may be needed to command the module on for testing.
8. Isolate the Fault: If a new, known-good heater element is available, it can be plugged into the harness under the seat to test the circuit. If the new element heats up and stays on, the original element is confirmed bad.

Parts You'll Likely Need

• Seat Heater Element Pad (Back or Cushion) (OEM #20792749 (Back, supersedes 15232560, 25911156), 20792748 (Cushion, supersedes 15232559)) — This is the most frequent point of failure. The internal wires break from normal use, causing an open circuit and triggering the code.
  Trusted brands: ACDelco (Genuine GM), Dorman (e.g., 628-040 Universal Kit, 641-106 Direct Fit)
  OEM price range: $150-$250
  Aftermarket price range: $80-$170
• Heated Seat Module Connector Pigtail (OEM #88988313 (ACDelco PT2389)) — Needed if the main connector on the heated seat module under the passenger seat is melted

Related Codes That Often Appear With This One

• B2425 — This is another GM-specific code for a heated seat fault, often appearing with B1935 as noted in TSB PIT5215A.
• B2430 — Also listed in TSB PIT5215A as a related heated seat diagnostic trouble code.
• B0081 — This code relates to the Passenger Presence System (PPS) for the airbag. It can be triggered along with B1935 if the under-seat wiring damage affects the PPS sensor or its wiring harness.
• B2180 — Another heated seat code mentioned in TSB PIT5215A that can be set by the same fault conditions.

Technical Service Bulletins (TSBs) & Recalls

• PIT5215A: Addresses symptoms where heated seat indicators remain on but the seat does not heat, potentially setting codes B1935, B2180, B2425, and/or B2430. It advises inspecting the accessory heated seat wiring harness for reversed seat back and bottom element connectors.
• 17-NA-010: While not directly for B1935, this TSB addresses related 'Service Airbag' messages with codes B0081/B0074 and warns against replacing the PPS module before checking for loose connectors and proper wire routing under the passenger seat, which is the same area of concern for B1935 wiring faults.

Platform-Specific Known Issues

• A known issue documented in TSB #PIT5215A involves the accessory heated seat wiring harness, which can cause this code along with B2425 and B2430 if the element connectors are reversed.
• The main power and ground pins on the heated/cooled seat module connector are known to be undersized for the electrical load, causing them to overheat and melt the connector, a common cause for this code on higher trim levels (LTZ, Denali, etc.).

Mechanic-Grade Diagnostic Values

• Driver's Seat Heater Element Resistance — expected: 6 to 8 ohms. Failure: Infinite resistance (OL) indicates a broken element. A value far outside the expected range can also indicate a problem.

Hidden / Shadow Codes Worth Checking

• B1935 with Symptom Byte 0E: The symptom byte '0E' specifically points to a circuit malfunction in the heated seat system, as referenced in TSB PIT5215A. This provides more specific information than the DTC alone, confirming the fault is not related to the airbag system. (see via A professional GM-specific scan tool like a Tech 2 (for pre-2014 models) or GDS2 is required to view symptom bytes.)

Scan Tool Commands That Help

• GDS2 (Global Diagnostic System 2): Module Diagnostics -> [Seat Module] -> Control Functions — After verifying wiring and elements are good, a technician can use this function to command the heated seat elements on and off directly from the scan tool. This helps determine if the control module itself is receiving the command from the switch and is capable of sending power to the elements, isolating the fault to the module if it fails to respond.

Wiring & Ground Locations

• Heated/Cooled Seat Control Module — Under the front passenger seat, typically held in place by two 10mm bolts.. This module controls both front heated seats. Its main power connector is a critical inspection point, as the power and ground pins are known to overheat and melt, causing an open circuit and setting code B1935.
• G301 — Under the left side of the passenger seat, on the floor pan.. This is a primary ground point for several components under the passenger seat, including the heated seat module. A loose or corroded connection at G301 can cause intermittent power loss and erratic operation of the heated seats, leading to this code.
• G302 — Under the right side of the passenger seat, on the floor pan.. This is another ground point for passenger-side components. While G301 is more directly related, ensuring all grounds in the area are clean and tight is good practice when diagnosing electrical faults.
• Heated Seat Module Connector (C3 on some diagrams) — The large 12-pin connector that plugs into the module under the passenger seat.. The large gauge Pink/White wire (Power) and Black wire (Ground) are the most important pins to inspect. These are the pins that are known to overheat and melt the connector housing.

Real Owner Repair Stories

• YouTube channel FTP Speed Shop (2011 Chevrolet Suburban) — Heated and cooled seats were not working.
  ❌ Tried (didn't work) The owner immediately suspected the common connector issue.
  ✅ What actually fixed it The owner found the main power pin on the heated seat module connector under the passenger seat was burnt. He replaced the connector with a new pigtail. For a more robust repair, he explained that GM only used one power and one ground pin, while the module has provisions for two of each. He wired the new pigtail to use both power and both ground terminals, splitting the electrical load to prevent the new connector from melting in the same way.
• Monte Carlo Forum user post (2004 Monte Carlo (process is identical for Tahoe element repair)) — Heated seat inoperative.
  ❌ Tried (didn't work) Initial diagnosis pointed to a bad heating element.
  ✅ What actually fixed it After partially removing the seat's leather cover, the owner found a small, visible burn spot on the heating element pad where a wire had broken. Instead of replacing the entire pad, he cut back the wire to a clean section, soldered in a small piece of 18-gauge wire to bridge the break, and insulated the repair with heat shrink tubing. This restored function to the heated seat.

OEM Part Supersession History

• 15232560, 25911156 → 20792749 — Part has been updated by the manufacturer over time.
  Heads up: These part numbers are for the seat BACK heater element. They are generally interchangeable for the specified model years.
• 13506705, 13509388 → 13510339 — Part has been updated by the manufacturer.
  Heads up: This is the heated/ventilated seat control module. Always verify the correct part number with the vehicle's VIN, as different modules were used depending on seat options.

Model Year Variations Within This Range

• 2007-2013 vs 2014: The factory diagnostic software used by dealerships changes. Models up to 2013 are typically diagnosed with the Tech 2 scan tool or its PC-based version, Tech2Win. The 2014 model year fully transitioned to the newer GDS2 (Global Diagnostic System 2) software. While both can read the code, the interface and specific diagnostic paths may differ slightly.