U.S. Gear Corporation, 1020 W119th, Chicago, IL  60643 -- Phone 888-874-3275

Dual Range Electrical
Troubleshooting Guide
(Manual Transmission)

There are four major components of the Dual Range electrical system:

a. Harness (#93-80043)– used to connect components and allow electrical current flow

b. Push/pull switch (#93-80029) – 2-speed axle type of switch usually clamped on gear shift lever

c. Shift module (#59-80012)– Black box (3"x3"x1") with wire connector attached to bottom of box. This is the controller of the electrical system.

d. Shift motor (#80-80055) – permanent magnet hi-torque motor. When in use it applies pressure to the shift spring. This motor will rotate both clockwise and counter-clockwise depending on direction of current flow. This motor is not internally grounded.

If the Dual Range fails to shift on command, first re-boot the computer shift module (#59-80012). To re-boot module, unplug the harness from the shift module for a couple minutes and then plug the harness back into the module. Attempt to shift the Dual Range. If re-booting the shift module does not correct the problem, continue with the following steps.

Visual Inspection – Inspect harness associated with Dual Range transmission from the push/pull switch in the cab of the truck to connections on the Dual Range itself. Once you are satisfied that there are no broken or damaged wires, proceed to operation check.

Locate shift module with harness attached to bottom of module. With 12 volt test light check:

a. Red wire – 12 gauge for battery power, not key control

b. Green wire – Good ground to clean metal connection (VERY critical).

c. Small red wire – 12 volts at push/pull switch

d. Blue wire – 12 volts only when push/pull switch is closed. No voltage when open.

e. White wire – 12 volts for approximately two seconds immediately after push/pull switch closes

f. Brown wire – 12 volts for approximately two seconds immediately after push/pull switch opens

Using 12 volt test light, bridge light between brown and white wires

Move push/pull switch up and down and test light should light each time the switch is moved. The test will also indicate that the module is providing ground circuit.

Motor test only – At connector of harness to module (black box), remove connector from module and, using two small 4" jumper wire, make connection between red wire pin and brown wire pin in connector, and from white wire pin to green wire pin. This should cause motor to operate and continue to run as long as both wires are connected. Motor should sound smooth and quiet. This is a bi-polar motor, so if it runs one direction it will run the other direction.

Any component not operating as outlined should be considered suspect and replaced. If you have any questions, please call the U.S. Gear Tech Line at 1-888-874-3275.

Dual Range Electrical Diagram

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Last modified: 06/06/08