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 MANUALSVOLKSWAGEN1991JETTA L4-1984CC 2.0L DOHCREPAIR AND DIAGNOSISRELAYS AND MODULESRELAYS AND MODULES - POWERTRAIN MANAGEMENTRELAYS AND MODULES - COMPUTERS AND CONTROL SYSTEMSENGINE CONTROL MODULEDIAGRAMSDIAGRAM INFORMATION AND INSTRUCTIONSWIRING DIAGRAM CIRCUIT IDENTIFICATION
1991 Volkswagen Jetta L4-1984cc 2.0L DOHC
Wiring Diagram Circuit Identification
1991 Volkswagen Jetta L4-1984cc 2.0L DOHCSECTION Wiring Diagram Circuit Identification
Wiring Diagram Terminal (circuit) Identification
Several wiring circuits in the vehicle's electrical system are identified with a number or letter designation. These circuits are identified the same in all wiring diagrams and are most commonly shown near the top of each page in the fuse/relay panel portion of the wiring diagram. The circuit designations may also be used to identify switch connector terminals (switch circuits). Following are the most common numbered/lettered circuits:
Terminal (circuit):
1 - Ignition coil/ignition distributor low voltage (typically used as an Engine Speed (RPM) signal for the tachometer)
15 - Switched Battery Positive Voltage (B+) from ignition/starter switch
30 - Battery Positive Voltage (B +), hot at all times
31 - Ground (GND)
50 - Starter control; switched B+ from ignition/starter switch
56 - Switched headlight B+ from light switch
58 - Switched parking light, taillight. illumination B+ from light switch
S (SU) - Key In ignition circuit: switched B+ from ignition/starter switch
X - Load reduction circuit; switched B+ from load reduction relay
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.