B1302

Code

Other B — Body

Accessory Delay Relay Coil Circuit Failure

Brand: Other

Type: B — Body

Views: UK: 26 EN: 158 RU: 33

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Page language: EN

Causes

Failed accessory delay relay (open coil or internal short)
Blown fuse or fusible link supplying the relay coil
Open or shorted wiring between relay and module or battery/ground
Corroded/loose relay socket or connector pins
Faulty body control module (BCM) or driver output
Water intrusion or physical damage to harness or relay

Symptoms

Accessories do not remain powered after key off, or do not operate at all
Accessory delay function inoperative or inconsistent
No click from accessory delay relay when activated
Related fuses may be blown
Associated body control or accessory warning messages on dash

What to check

Read and record DTC and freeze-frame data with a scan tool
Visually inspect relay, relay socket, wiring, and connectors for corrosion, damage, or water ingress
Check fuses and fusible links in accessory/BCM circuits
Listen for relay click when accessory delay should energize
Swap relay with identical known-good relay (if available)
Measure battery voltage at relay supply pin with ignition ON and OFF

Signal parameters

Coil supply voltage: ~Battery voltage when relay is commanded (approx. 11–14 V)
Coil resistance: typical range 50–200 ohms (vehicle-specific) — consult vehicle-specific data
Control signal: BCM typically supplies ground or +12 V to one coil terminal when commanding relay
Operating current: generally tens to a few hundred mA when coil energized

Diagnostic algorithm

Verify complaint, retrieve and record freeze-frame and any related codes with a scan tool.
Inspect relay and socket for corrosion, melted plastic, or water damage. Check associated fuses; replace any blown fuses and note if they blow again.
With ignition OFF, remove accessory delay relay and measure coil resistance across the coil terminals. If open or significantly out of spec, replace relay.
Install relay and backprobing (or use a fused jumper) to check coil supply pin for battery voltage with ignition ON/ACC. If no supply, trace and repair power feed (fuse, fusible link, wiring).
Command accessory delay ON (with scan tool or intended ignition position) and check control pin voltage: expect BCM-driven change (ground or +12 V depending on design). If control signal missing, check BCM outputs, wiring continuity from BCM to relay socket, and connector pins.
Perform continuity checks to ground from relay socket ground terminal; repair any poor grounds.
If relay and wiring are good but control signal present and coil not actuating, replace relay. If relay actuates but code returns, inspect for intermittent wiring; perform wiggle tests while monitoring signal.
If wiring and relay are good but no proper control signal from BCM, follow module-level diagnostics per manufacturer: check BCM power/ground, connectors, and programming/flash status. Replace BCM only after confirming harness and inputs are correct.
After repairs, clear codes and confirm correct operation through functional test and a short road/test cycle or repeat accessory delay cycles.

Likely causes

Relay coil open or shorted
Corroded connector or poor ground at relay socket
Blown fuse feeding relay coil
Open circuit in control wire from BCM to relay
Intermittent wiring break (chafing, pinched harness)

Fault status

⚠️ Status

Stored when the body control module detects an abnormal condition in the accessory delay relay coil circuit (open, short, high resistance, or no driver response).

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours