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.
Transfer Case Range Select Switch Input (Neutral & 4HI/4LO Select Switch)
The FDCM will support circuitry which interfaces to the system's Transfer Case Range Select Switch, including a Transfer Case Range Select Switch voltage supply and a Transfer Case Range Select Switch input. The purpose of this circuitry is to determine the mode currently being requested by the operator via the resistance ladder network in the shifter assembly, where the Transfer Case Range Select Switch is packaged.
The NEUTRAL Select Switch Input will provide the operator with the ability to place the Transfer Case in Neutral. The 4HI/ 4LO Select Switch Input will provide the operator with the ability to place the transfer case in 4HI or 4LO. The NEUTRAL Select Switch is a momentary contact switch and the 4HI/4LO Select Switch is a 2-position toggle or a momentary contact switch and both these switches are provided through a resistor network for diagnostic purposes. The input will have an internal 1.0K +/- 1% pull-down resistor to ground.
As the selected position in the 4HI/4LO Switch varies and/or the NEUTRAL Switch is depressed or not, the resistance between the module's Transfer Case Range Select Switches voltage supply and Transfer Case Range Select Switches input will vary. Hardware, software, and calibrations within the FDCM will be provided that interpret the external resistance between the module's Transfer Case Range Select Switches voltage supply and Transfer Case Range Select Switches inputs as given in the table below:
| STEP | RESISTANCE RANGE | REQUIRED INTERPRETATION |
|---|---|---|
| A | 63<111<140.4 | Fault Condition (short) |
| B | 309.7<337<364.39 | NEUTRAL from 4LO(1) |
| C | 380.93< 414<448.20 | NEUTRAL from 4HI(1) |
| D | 910.87< 990< 1071.72 | 4LO |
| E | 2024.17< 2200< 2381.61 | 4HI |
| F | Greater Than 8661.5<9000<9343 | Fault condition (open) |
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.