Tacoma Seat Heater Connector Failure: the Problem and the Fix

Services @ TS
Oct 28
2 min read

Pin-pointing the culprit connector — Pinpointing the culprit

Owners of certain Toyota Tacoma (2011–2018, possibly earlier/later but we haven't seen any evidence of it) WITH factory seat heaters, may experience a sudden seat heater failure that traces back to a small but critical part of the system: the connector at the seat heater control module. The issue is common enough that Toyota released a Technical Service Bulletin (T-SB-0130-18) to address it. For even more info about folks who went thru the same issue: https://www.tacomaworld.com/threads/factory-heated-seats-failure.528038/

Never let out the OEM smoke — The result of letting out the OEM smoke.

The underlying problem is thermal damage caused by high contact resistance. Over time, vibration, oxidation, or a slightly loose terminal increases resistance at the contact point. That resistance generates heat, which softens the surrounding plastic and reduces the spring tension of the terminals. As the connection loosens, resistance rises even further, accelerating heat buildup in a self-reinforcing cycle known as thermal runaway.

Once this process begins, the connector housing often melts, and the seat heater shuts off completely. In severe cases, heat damage can extend into the seat heater control module itself. Toyota’s service bulletin addresses the issue by replacing the entire seat heater assembly, including the module and cushion cover, which is both costly and unnecessary for out-of-warranty vehicles. In fact in our customer discussion this morning, he was told this was an $1800 solution at the Toyota dealership.

To provide a targeted and permanent repair, Tolerance Stack put together a Seat Heater Computer Connector Repair Kit that replaces the damaged connector and pin terminals. You will likely also need a replacement heater control module (Toyota part no: 87501-OC020) or the entire heater assembly (Toyota part no. 87510-04050) which includes the heating element, a new wire harness, a new control module, and of course a new connector.

The kit includes the new connector housing and four replacement terminals (one is unused in the housing). Installation requires trimming back any discolored or brittle wire to expose clean copper, crimping on the new terminals with a proper ratcheting crimp tool, and inserting them into the housing in their original order.