Locating the OBD2 port on your 1999 Jetta is the first step in diagnosing any trouble codes or understanding your vehicle’s health. This port, your gateway to your car’s computer, is essential for mechanics and DIYers alike. If you’re having trouble connecting your OBD2 scanner to your 1999 Jetta, a blown fuse could be the culprit. This article will guide you to the OBD2 port location, pinpoint the relevant fuse, and provide a complete fuse list for your 1999 Volkswagen Jetta MKIV.
Finding the OBD2 Port in Your 1999 Jetta
The OBD2 port, or On-Board Diagnostics II port, is a standardized connector used in most vehicles for accessing the car’s diagnostic information. In a 1999 Volkswagen Jetta (MKIV generation), you’ll typically find the OBD2 port located:
- Under the dashboard on the driver’s side. Look for it in the area above the pedals and below the steering wheel column.
- It’s usually not hidden behind a panel but is openly accessible. You should be able to see it by looking under the dash.
- The port is trapezoidal in shape with 16 pins. This is the standard OBD2 port shape.
Once you’ve located the port, you can connect your OBD2 scanner to read diagnostic trouble codes (DTCs) and access live data from your vehicle’s systems. However, if your scanner is not powering on or connecting, a fuse issue is a common cause, specifically the fuse powering the Data Link Connector (DLC).
Fuse #12: The OBD2 Port Power Supply Fuse
In your 1999 Jetta’s fuse box, Fuse #12 is responsible for providing power to the Data Link Connector (DLC), which is your OBD2 port. If this fuse is blown, your OBD2 scanner won’t receive power, and you won’t be able to establish a connection with your car’s computer.
- Fuse Location: The fuse box in a 1999 Jetta MKIV is located on the driver’s side of the dashboard. You’ll usually find it behind a panel on the side of the dash, accessible when the driver’s door is open.
- Fuse Identification: Refer to the fuse box diagram, usually located on the inside of the fuse box cover. Locate Fuse position #12.
- Fuse Rating: Fuse #12 is a 7.5 Amp fuse.
- Troubleshooting:
- Inspect the Fuse: Carefully remove Fuse #12 from the fuse box. You can use a fuse puller tool or needle-nose pliers.
- Visual Check: Examine the fuse. A blown fuse will often have a broken filament inside or appear burnt. However, sometimes a fuse can be faulty without visual signs.
- Replace the Fuse: Even if the fuse looks okay, it’s good practice to replace it with a new 7.5 Amp fuse.
- Test Your OBD2 Scanner: After replacing the fuse, try connecting your OBD2 scanner again to see if it powers on and connects to your Jetta.
If replacing Fuse #12 resolves the issue, you’ve likely found the problem. If the fuse blows again immediately or your OBD2 scanner still doesn’t work, there might be a more serious electrical issue, such as a short circuit in the OBD2 port wiring or a problem with the vehicle’s computer system. In such cases, it’s recommended to consult a qualified automotive electrician.
Complete 1999 Jetta MKIV Fuse List
For your convenience and as a valuable resource for 1999 Jetta owners, here is a complete fuse list for the MKIV model. This list can be helpful for diagnosing various electrical issues throughout your vehicle.
MKIV Fuse List
Top Section (Left to Right by Column)
- Washer nozzle heaters, glove compartment light, memory seat control module (10A)
- Turn signal lights (10A)
- Fog light relay, instrument panel light dimmer switch (5A)
- License plate light (5A)
- Comfort system, cruise control, Climatronic, A/C, heated seat control modules, automatic day/night interior mirror, control module for multi-function steering wheel, control unit in steering wheel (7.5A)
- Central locking system (5A)
- Back-up lights, speedometer vehicle speed sensor (VSS) (10A)
- Open
- Anti-lock brake system (ABS) (5A)
- Engine control module (ECM): gasoline engine (10A); diesel engine, Model Year 2000 > (5A)
- Instrument cluster, shift lock solenoid (5A)
- Data Link Connector (DLC) power supply (7.5A)
- Brake tail lights (10A)
- Interior lights, central locking system (10A)
- Instrument cluster, transmission control module (TCM) (5A)
- A/C clutch, after-run coolant pump (10A)
- Open
- Headlight high beam, right (10A)
- Headlight high beam, left (10A)
- Headlight low beam, right (15A)
- Headlight low beam, left (15A)
- Parking lights right, side marker right (5A)
- Parking lights left, side marker left (5A)
Bottom Section (Left to Right by Column)
- Windshield and rear window washer pump, windshield wiper motor (20A)
- Fresh air blower, Climatronic, A/C (25A)
- Rear window defogger (25A)
- Motor for rear windshield wiper (15A)
- Fuel pump (FP) (15A)
- Engine control module (ECM) gasoline engine (15A); diesel engine (10A)
- Power sunroof control module (20A)
- Transmission control module (TCM) (20A)
- Injectors: gasoline engine (10A); diesel engine (15A)
- Headlight washer system (20A)
- Open
- 12 V power outlet (in luggage compartment) (30A)
- Fog lights (15A)
- Terminal (86S) on radio, Instrument cluster (10A)
- Central locking system (with power windows), luggage compartment light, remote/fuel tank door, motor to unlock rear lid (15A)
- Emergency flashers (15A)
- Dual tone horn (20A)
- Cigarette lighter (15A)
- Radio (25A)
- Engine control elements (10A)
- Heated seats (15A)
Fuse Arrangements in Fuse Bracket/Battery:
- S162. Glow plugs (coolant) (50A)
- S163. Fuel pump (FP) relay/glow plug relay (50A)
- S164. Coolant fan control (FC) control module/coolant fan (40A)
- S176. Relays panel interior (110A)
- S177. Generator (GEN) (90 Amp.) (110A). Generator (GEN) (120 Amp.) (150A)
- S178. ABS (hydraulic pumps) (30A)
- S179. ABS (30A)
- S180. Coolant fan (30A)
Having this fuse list readily available can save you time and effort when diagnosing electrical problems in your 1999 Jetta. Remember to always replace a blown fuse with one of the same amperage rating to prevent further electrical damage. If you are unsure about any electrical repairs, always consult a professional mechanic.
