B3620

Code

Generic B — Body

Door Lock Actuator Circuit Short to Ground

Brand: Generic

Type: B — Body

Views: UK: 18 EN: 23 RU: 23

AI status

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Page language: EN

Causes

Pinched, chafed or damaged wiring in the door harness contacting chassis ground
Corroded or water-damaged connector creating a ground path
Internal short in the door lock actuator motor or solenoid
Aftermarket alarm/remote or wiring splice incorrectly tied to ground
Faulty BCM/door module output transistor or driver
Blown or intermittent fuse/relay due to repeated shorting

Symptoms

One or more door locks do not operate (stuck locked or unlocked)
Blown fuse for door locks or repeated fuse failures
Intermittent lock/unlock operation or only a clicking sound
Battery drain or parasitic draw in some cases
Related body module fault messages or loss of remote locking functionality

What to check

Check stored DTCs for related door/BCM codes and note freeze frame data
Inspect fuses and relays for the door lock circuit; replace blown fuses only after finding cause
Visual inspection of door harness, grommet and connector for chafing, corrosion or water intrusion
Operate lock/unlock while probing voltage at the actuator connector (backprobe) with door panel removed
Measure resistance between the control wire and chassis ground with connector disconnected
Swap with a known-good actuator (if available) or disconnect actuator to see if short clears

Signal parameters

Control output: 0 V (ground) or battery voltage (~12 V) when not commanded depending on vehicle driver topology; when commanded expect a switched voltage close to battery (~11–13 V) at the actuator
Actuator coil resistance: typically low (few ohms to tens of ohms) — expected to be measured as a finite resistance when disconnected from controller (consult vehicle-specific spec)
Current draw when operating: commonly hundreds of mA up to a few amps during motor stall; a direct short to ground will show near-infinite current draw limited by fuse/driver
Inactive circuit: should not measure continuity to chassis ground on the control/power feed (open/high resistance)
Driver output behavior: BCM should not show a sustained overcurrent; repeated overcurrent events usually set this code

Diagnostic algorithm

Record DTCs and any additional body/communication codes. Clear codes after noting and retest to see if B3620 returns.
Inspect fuses/relays for the door lock circuit. Do not replace a fuse repeatedly without finding the short.
Perform a visual inspection of the door harness, especially through the door jamb boot. Look for broken wires, rubbed insulation, or pinched sections.
Remove the interior door panel and disconnect the actuator connector. Check the connector pins for corrosion, bent pins or contamination.
With the actuator disconnected, measure resistance from the control/power feed to chassis ground. A low resistance indicates a short in wiring or an accessory tap.
Command lock/unlock while monitoring voltage at the BCM output pin with the actuator disconnected. If the output is shorted to ground, voltage will not appear or will collapse and may set current fault flags.
If wiring appears OK, bench-test the actuator by powering it through a fused jumper from a known good fused 12 V source (observe proper polarity and use a fuse/test lamp to limit current). Replace actuator if it shorts when powered.
If actuator bench test is good and wiring shows a short only when connected to BCM, suspect BCM/door module output failure. Confirm by measuring driver output with scope or substitute known-good module where practical.
Repair or replace damaged wiring, connectors or actuator. Ensure grommet seals in the door jamb are intact to prevent reoccurrence from flex/corrosion.
After repair, clear DTCs, operate the locks multiple times and confirm normal operation and no recurrence of the code.

Likely causes

Damaged insulation where the harness passes through the door jamb (most common)
Contaminated connector (water/corrosion) at the actuator
Failed actuator with internal short between power and ground windings
Incorrect or damaged aftermarket wiring tapping into lock circuit
BCM output stage failure if wiring and actuator check OK

Fault status

⚠️ Status

Door lock actuator control circuit short to ground detected. Output current/voltage abnormal; actuator operation may be disabled and related fuses may be affected.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours