B1975

Code

Other B — Body

Passenger's Seat Recline Back Switch Circuit Short to Battery

Brand: Other

Type: B — Body

Views: UK: 26 EN: 30 RU: 21

AI status

Completed

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Page language: EN

Causes

Wiring insulation damaged and contacting a +12V source (short to battery)
Terminal or connector pin pushed into contact with battery-positive conductor
Internal short inside the recline-back switch
Short inside the seat control / body control module
Aftermarket accessories or improper repairs that tapped into a power feed
Corrosion or water ingress creating unintended positive feed

Symptoms

Recline-back function inoperative or operates intermittently
Seat back moves unexpectedly or is stuck in one position
DTC B1975 stored in body/seat control module
Related fuses blow or are repeatedly failing
Possible battery drain when vehicle is off

What to check

Read and record all stored codes and freeze frame data with scan tool; note ignition/seat positions when code set
Visually inspect seat wiring harness, especially through seat tracks, hinges and where harness exits the seat
Inspect connectors at the recline switch and seat control module for corrosion, bent pins or pushed-in terminals
Check fuses and any seat-relay for signs of overheating or repeated failure
With ignition off, disconnect the recline switch connector and test for continuity to battery positive to isolate the short
With ignition on, measure voltage at the switch connector pins while operating the switch (compare to expected values)

Signal parameters

Nominal battery voltage when circuit is driven: ~11–14 V (engine running or ignition ON)
Expected voltage on recline-back signal with switch OFF: ~0 V (or open circuit) — a steady battery voltage indicates a short to battery
Switch closed continuity: low resistance typically
Open switch resistance: very high/OL (>10 kΩ) or open circuit
If circuit uses a module driver, look for module command low (~0 V) and battery feed high (~12 V) on the harness as appropriate

Diagnostic algorithm

Retrieve and record DTCs, then clear codes. Attempt to reproduce fault to confirm persistence of B1975.
Perform a visual inspection of the passenger seat wiring (seat base, track, hinge points, side trim). Look for chafing, pinched insulation or melted areas.
With ignition OFF and battery disconnected per manufacturer SRS procedure, unplug the recline-back switch connector. Use an ohmmeter to check for continuity between the switch circuit pin and battery positive. Continuity indicates a short in harness, switch, or module.
If short is present with switch disconnected, isolate segments by unplugging connectors at the seat control module and intermediate points; repeat continuity checks to find the segment containing the short.
If the short disappears when the switch is disconnected, bench-test the switch (or replace with known-good unit) and inspect its internal terminals for short to battery.
With ignition ON, carefully reconnect and back-probe the harness to measure voltage at the switch connector with the switch in both positions. Confirm proper change between approx. 0 V and battery voltage only when expected.
Inspect and test any associated fuses/relays and the seat control/module outputs. If module outputs are shorted internally, consult factory procedures — module replacement may be required.
Repair damaged wiring (splice/replace harness sections, replace connectors) or replace defective switch/module as indicated. Secure and protect harness where it passes through moving parts.
After repair, clear codes, perform full function test of seat adjustments, and re-scan to ensure B1975 does not return. Verify no parasitic draw if suspected.

Likely causes

Pinched wire where harness runs through seat track or seat frame
Broken wire with exposed conductor contacting a 12V source
Failed switch with internal short to the battery feed
Damaged connector (mating side) providing constant battery feed
Faulty seat control module output stage shorted to battery

Fault status

⚠️ Status

Stored when the passenger seat recline-back switch circuit is detected at battery voltage when it should be open or inactive. The body/seat control module records B1975 and may disable the recline function or set related occupant detection/seat subsystem protections. Inspect wiring, connectors, switch and module for short to battery.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-2.5 hours