B3517 – Left Rear Door Switch Express Up/Down Window Contact Shorted to GND

B3517 means the vehicle has detected a problem in the left rear door power window switch circuit for the express up/down contact, specifically a condition that appears shorted to ground. You will usually notice the left rear window express feature stops working first, or the window may only move in one direction, work only while holding the switch, or act inconsistently. This code is a Body (ISO/SAE controlled) diagnostic code and points to a suspected trouble area in the switch input and its related wiring, connectors, or module input circuitry, not a guaranteed failed part.

System: Body | Standard: ISO/SAE Controlled | Fault type: General

Definition source: SAE J2012 naming/structure guidance (verify exact wording against your official DTC dataset)

The B3517 code points to the left rear door switch express up/down window contact signal being detected as shorted to ground. Check the left rear door switch, door-jamb wiring harness, and connectors first for damage, moisture, or pin fit issues before replacing parts.

What Does B3517 Mean?

The meaning of B3517 is that a control module sees the left rear door window switch “express up/down” contact circuit pulled low in a way that matches a short-to-ground condition. In plain terms, the vehicle thinks the express switch input is stuck at ground or being forced low when it shouldn’t be, so it flags the B3517 diagnostic code. Diagnostically, this does not prove the switch itself is bad; the same symptom can be caused by wiring chafed to ground in the door or hinge area, water intrusion in connectors, terminal corrosion, or an issue with the module input that monitors the switch signal.

Theory of Operation

In a typical power window system, the door switch (or a door module integrated with the switch) sends distinct electrical signals for “up,” “down,” and “express” requests. The monitoring module (often a door module or body control module, depending on vehicle design) expects the express up/down contact signal to change state only when the switch is intentionally pressed into the express detent.

When that monitored input is shorted to ground, the module may interpret the signal as constantly active, invalid, or implausible compared to other switch states. To prevent unintended window operation and to protect the circuit, the module may disable express behavior, revert to manual-only operation, or ignore the request and store B3517.

Symptoms

B3517 symptoms usually show up as left rear power window control problems, especially with the express feature.

• Express up/down inoperative: the left rear window does not perform one-touch (express) up or down even though manual movement may still work.
• Manual-only operation: the window moves only while holding the switch, with express mode disabled.
• Intermittent window response: the left rear window works sometimes, then stops, especially after closing the door or driving over bumps.
• Window behaves unexpectedly: the window may stop early, hesitate, or not respond correctly to quick “express” inputs.
• Switch feels normal but no action: the switch clicks into the express detent but the window control does not react as expected.
• Related warnings/messages: some vehicles may display a window/door module message or store additional body codes related to the left rear door or window controls.

Common Causes

• Chafed, pinched, or rubbed-through wiring in the left rear door harness that allows the express up/down contact circuit to touch ground
• Moisture intrusion or corrosion in the left rear door switch connector or door-to-body harness connector creating an unintended ground path
• Loose, backed-out, or spread terminals at the switch, door module (if equipped), or junction connector increasing the chance of a short-to-ground condition
• Contamination inside the left rear door switch (spills, dirt, oxidation) causing the express contact circuit to read as grounded when it should not
• Damaged wiring where the harness flexes at the door hinge area (common high-movement point) leading to intermittent or hard short to GND
• Improperly installed aftermarket equipment or prior door repair affecting window switch wiring routing, insulation, or connector seating
• Shared ground or ground splice issue in the door (high resistance, corrosion, or misrouting) that contributes to abnormal switch signal behavior
• Body control module/door module input circuit concern (rare), where the module interprets the express contact as shorted to ground despite external wiring checks

Diagnosis Steps

Use a scan tool capable of accessing Body/BCM (and any door module data), a digital multimeter, and the correct wiring diagram for your exact year/make/model. You’ll be checking for a short-to-ground on the left rear express up/down contact circuit, verifying power/ground quality, and inspecting high-flex harness areas. Back-probing pins and using a fused jumper can help avoid terminal damage.

1. Verify the B3517 code is current (not just history) and record any other Body-related DTCs; note when it sets (door movement, window use, key cycles).
2. Check left rear window operation: confirm whether normal up/down works, whether express up/down is inoperative, and whether the switch feels sticky or inconsistent.
3. Perform a careful visual inspection of the left rear door switch, bezel, and connector area for liquid contamination, broken plastic, or signs of overheating.
4. Inspect the door-to-body rubber boot and harness for pinched sections, cracked insulation, or previous repairs; gently flex the harness while watching for symptom changes.
5. With the scan tool, view BCM/door module live data (if available) for the left rear window switch inputs; look for an input that remains “active/pressed” or “grounded” when untouched.
6. Key off, disconnect the left rear door switch connector. Recheck the scan tool input (if it updates with switch disconnected) and see if the “pressed/grounded” indication changes; this helps separate a switch issue from a harness/module issue.
7. Using the wiring diagram, identify the express up/down contact circuit pin. With the switch unplugged, test resistance from that circuit to chassis ground. A low-resistance reading suggests a short-to-ground in the harness or connector path.
8. If the circuit shows short-to-ground, isolate the location by disconnecting intermediate connectors (door-to-body, kick panel/junction connectors, door module connectors if equipped) and retest after each separation until the short disappears.
9. If the circuit does not show short-to-ground with the switch unplugged, test the switch itself for unintended continuity to ground across its express contact path (compare released vs pressed states per the wiring logic shown in the diagram).
10. Check powers and grounds feeding the switch/module: confirm stable ground integrity (voltage drop testing under load is best) and verify any reference or pull-up circuits behave normally when the switch is connected/disconnected.
11. After repairs, clear codes and perform a functional test: operate the left rear window through normal and express commands, then drive/operate doors to reproduce the original set condition and confirm B3517 does not reset.

Professional tip: Don’t replace the left rear door switch just because B3517 mentions the switch contact. First prove whether the express contact circuit is actually shorted to GND with the switch unplugged; if it is, the problem is in the harness/connectors (most often in the door jamb flex area), not the switch itself.

Possible Fixes

• Repair or replace damaged wiring in the left rear door switch/door harness, especially where it passes through the door jamb boot
• Clean, dry, and secure connectors; remove corrosion and address moisture intrusion (reseat connectors, repair seals as needed)
• Repair terminal fit issues (re-pin, tighten, or replace backed-out/spread terminals) at the switch, door-to-body connector, or module connector
• Replace the left rear door window switch if testing confirms the express up/down contact is internally shorted to ground
• Correct wiring routing or undo improper aftermarket/previous repair modifications that can create a short to GND
• Relearn/initialize the window express function if required by the vehicle after power loss or component replacement (procedure varies by make/model)
• Replace or reprogram the appropriate control module only after circuit integrity and switch function are verified (rare)

Can I Still Drive With B3517?

Yes, you can usually still drive with the B3517 code because it’s a Body-system fault related to the left rear door switch express up/down window contact circuit being detected as shorted to ground (GND). In most cases it won’t affect engine performance, braking, or steering, but you may lose express window operation, have a window that won’t respond correctly, or experience unintended window behavior. If the window can’t be controlled reliably (especially if it won’t close), address it soon to prevent water intrusion, theft risk, or pinching hazards.

How Serious Is This Code?

B3517 is usually a moderate-severity convenience and safety-related electrical issue rather than a drivability problem. It’s mostly an inconvenience when the only impact is that express up/down stops working on the left rear window. It becomes a safety or security issue if the window moves unexpectedly, won’t close, or causes the door switch to behave erratically—especially with children in the rear seat or during bad weather. Ignoring it can also lead to repeated battery draw concerns or additional Body control faults if the short to GND is affecting shared wiring or module inputs.

Repair Costs

Repair cost depends on whether the confirmed root cause is wiring, connector condition, a switch or module issue, or the labor needed to diagnose the fault correctly.

Last updated: March 22, 2026