Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSGMC1999SAVANA SPECIAL 7.4 JREPAIR AND DIAGNOSIS (SINGLE PAGE)BODY & FRAMEDOOR LOCKSANTI-THEFT SYSTEMDIAGNOSTIC TESTSDTC B0687: SECURITY SYSTEM INDICATOR LOWCIRCUIT DESCRIPTION
1999 GMC Savana Special 7.4 J
Circuit Description
1999 GMC Savana Special 7.4 JSECTION Circuit Description
The VIM controls the operation of the SECURITY indicator lamp by providing ground at terminal M. Lamp control is based upon inputs from the following components:
- VCM (Class 2 Data, terminal C and terminal D)
- Ignition Switch (Ignition 1, Terminal J, CKT 39)
- Brake Pedal (Stop Lamps, Terminal L)
- SECURITY Indicator (SECURITY Indicator Control, Terminal M)
- Signals Received From The Transmitter In The Key Fob
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.