Hi there!It may be a problem with the back up light switch itself.Here is some info for testing it.Hope this helps!Thanks
REMOVAL, INSTALLATION & ADJUSTMENT
See Figures 1, 2 and 3
The neutral safety and reverse light switch is mounted on and actuated by the transmission select shaft which protrudes from the side of the transmission housing. It is located directly underneath the select lever and select cable assembly which is used to control the select shaft from the linkage in the passenger compartment.
The shifter select cable is attached at one end to the shift linkage by an e-ring and a cable end clip (though the center console must be removed and the manual shift linkage assembly must be unbolted and repositioned for access). But, the other end of the cable is attached to the transmission manual select lever with a threaded end that may require adjustment if any of the mechanical components in the linkage are replaced or if the lock and adjusting nuts are ever disturbed. Be careful not to touch the nuts on the select cable or it will require adjustment after the switch is replaced. If the cable is ever replaced, or the nuts are turned, then simply adjust the cable so that there is little or no play when both the manual select lever (on the transmission) and the gear select lever (on the floor the passenger compartment) are both in neutral.
Although you will be able to access the switch fine whether the front of the rear of the vehicle is raised, we recommend raising the rear in case you need to spin the rear driveshaft to check if the transmission is in gear or not.
Fig. 1: The neutral safety position (shift lever) switch is mounted to the side of the transmission assembly-4-speed models shown Fig. 2: Before tightening the fasteners, make sure the switch and selector lever are both in Neutral Fig. 3: On 3-speed models, switch adjustment is accomplished by checking continuity across the 2 terminals of connector C1
See Figures 4, 5, 6 and 7
The neutral safety switch is designed to keep the engine from starting in any gear, only allowing the starter to operate in Park (P) or Neutral (N). The switch also functions as the reverse light switch, but should ONLY turn these lights on in Reverse (R). To verify proper switch operation:
Fig. 4: Shift switch coupler terminal identification for early-model 4-door Sidekick (except Sport) and Tracker models equipped with 4-speed transmissions-the switch condition can be checked using the shift switch coupler Fig. 5: Use this chart to check continuity across the shift switch coupler terminals in various gear positions-early-model 4-door Sidekick (except Sport) and Tracker Fig. 6: For the late-model Sidekicks, Trackers and the Sidekick Sport, the switch connector is mounted directly to the top of the selector switch and the terminals are arranged differently than on the early-model 4-door Sidekick or Tracker Fig. 7: Use this chart to check continuity across the shift switch coupler terminals in various gear positions-late-model Sidekick, Tracker and Sidekick Sport models
The 4-speed shift switch coupler is usually found above the transmission housing in the transmission tunnel. Although access to it may be possible from the passenger compartment on most early 4-door models (if you remove the selector lever), it is probably easier in most cases to get at it from under the truck. To do this, trace the wires back from the switch at the side of the transmission until you can disengage the connector from the vehicle harness. For late-model Sidekicks and Trackers, along with the Sidekick Sport, the wiring connector is mounted directly on top of the switch.
REMOVAL & INSTALLATION
See Figure 1
For Suzuki vehicles, the manual transmission reverse light switch is usually threaded into the side or top of the transmission housing. The switch will almost always be found on the upper left side of the transmission case, just behind the bell housing. Do not confuse the switch with the 4WD switch which is usually mounted further back, on top of the transfer case (which is integral with the transmission on all but Samurai models).
Before attempting replacement, check the position of the switch, relative to the position of the transmission filler plug. If it is located higher on the transmission case then the plug, you should be able to replace the switch without losing any transmission gear oil. But if the switch is equal to or lower of the case than the plug, you should have a drain pan handy to catch any escaping fluid. In this second case, you should still be able to replace the switch without having to completely drain the fluid. The trick is to have the replacement in one hand while you unthread the old switch. Once the old switch is loose, quickly withdraw it while positioning and threading the replacement in its place. If done correctly, a minimum amount of gear oil will escape.
Fig. 1: The reverse light switch is threaded into the top or side of the transmission housing-this Sidekick/Tracker has the switch on the upper left side, just behind the bell housing
Most Suzuki models utilize a switch whose pigtail is permanently attached to the base of the switch. On these models, follow the switch wiring back through the rubberized-plastic coated metal wiring clips to locate the harness connector. Carefully release the lock-tab and disconnect the wiring.
WARNING DO NOT overtighten the switch, you could damage the switch or the aluminum transmission housing.TESTING
See Figures 2, 3 and 4
Fig. 2: With the transmission shifter in Reverse, check for continuity across the switch's 2 wiring terminals Fig. 3: On late-model vehicles, a harness connector is located behind the intake that you can use for testing ... Fig. 4: ... at this connector the reverse light circuit is checked between terminals 3 and 4
If the reverse lights stop working, and a voltage check shows NO POWER to the reverse light sockets when the transmission shift lever is in reverse, check the switch for proper continuity using an ohmmeter. The test can either be conducted directly across the 2 terminals on the switch wiring connector, or for Sidekick, Tracker and X-90 models, it can also be checked underhood using the harness connector at the back of the intake manifold. If the second option is taken, release the wiring from the clamp at the back of the manifold, separate the wiring and check for at terminals 3 and 4 (at one end of the 6 terminal connector).
The switch should test continuous ONLY when the transmission shift lever is in Reverse.