Multifunction Electronic Modules: Other Mercury Mariner I

Module Controlled Functions

The smart junction box (SJB) is the multifunction electronic control module on this vehicle. The SJB is a combination of a multifunction control module and an interior power junction box. SJB functions control multiple systems, which include

1. illuminated entry and interior lamps
2. exterior lamps
3. power door locks
4. smart locks
5. remote keyless entry (RKE) keypad
6. RKE system
7. warning chimes
8. rear windshield wiper

The SJB is located under the front passenger side floor console. For removal information, refer to SMART JUNCTION BOX (SJB) . For additional information on the interior lamps and illuminated entry, refer to INTERIOR LIGHTING . For additional information on the exterior lighting, refer to EXTERIOR LIGHTING . For additional information on the power door locks, the RKE keypad, and the RKE system, refer to HANDLES, LOCKS, LATCHES AND ENTRY SYSTEMS . For additional information on the rear windshield wiper, refer to WIPERS AND WASHERS . For additional information on the perimeter anti-theft, refer to ANTI-THEFT - PERIMETER A. For additional information on the climate control system, refer to CLIMATE CONTROL SYSTEM-GENERAL INFORMATION (Escape, Mariner), or CLIMATE CONTROL SYSTEM - HYBRID (Escape Hybrid). For additional information on the warning chimes, refer to WARNING DEVICES .

Smart Junction Box (SJB)

On Escape, refer to COMPUTER DATA LINES for schematic and connector information.

On Mariner, refer to COMPUTER DATA LINES for schematic and connector information.

Connector Circuit Reference

Smart Junction Box (SJB) C2280a

Scheme 51

Smart Junction Box (SJB) C2280b

Scheme 52

Possible Causes

1. SJB power circuit 1052 (TN/BK) open
2. SJB ground circuit 570 (BK/WH) open
3. SJB

Scheme 53

Scheme 54

1. A1 CHECK THE SJB GROUND CIRCUIT Key in OFF position. Disconnect: SJB C2280a. Measure the resistance between the SJB C2280a-21, circuit 570 (BK/WH), harness side and ground. Is the resistance less than 5 ohms? Yes : GO to A2. No : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.
2. A2 CHECK THE SJB POWER SUPPLY Connect: SJB C2280a. Disconnect: SJB C2280b. Key in ON position. Measure the voltage between the SJB C2280b-4, circuit 1052 (TN/BK), harness side and ground. Is the voltage greater than 10 volts? Yes : REFER to «MODULE COMMUNICATIONS NETWORK»(ref-232245) to continue communication diagnosis. No : REPAIR the circuit. CLEAR the DTCs. REPEAT the self-test. CARRY OUT the data link diagnostics test.

Scheme 55