The body hoist system has two modes that will not allow the ECM to follow the requests of the operator.
The body hoist system will be forced into hold under ANY of the following six conditions.
- After power is applied to the ECM the body hoist system will be forced into hold during the first two seconds.
- After the engine starts the body hoist system will be forced into hold for the first two seconds.
- After the start relay has been energized the body hoist system will be forced into hold for the first two seconds.
- The body hoist system will be forced into hold if the ECM records an active fault with the hoist lever.
- The body hoist system does not respond when any combination of faults with the solenoids has occurred and the body hoist system fails to respond to any requests from the operator.
Note: This is an example. If the solenoid that raises the bed is shorted to the +battery then the ECM will activate the solenoid that is used to lower the bed. This is done in order to keep the bed from moving. At the same time, the override would be activated. This will stop the bed from moving after the diagnostic code is removed. When the solenoid has an open circuit condition the ECM will activate the override.
- The body hoist system will be forced into hold if the engine is not running AND the operator is not trying to lower the bed with a dead engine.
If none of the above conditions are true, the override will stay active until the hoist lever is placed in the hold position or the hoist lever moves through the hold position.
Lowering the Bed with a Dead Engine
Lowering the bed with a dead engine may be necessary under certain conditions.
The engine must be OFF. The key start switch must be in the ON position. The battery must be fully charged.
Follow the steps below in order to lower the bed with a dead engine .
This procedure should be performed with two people. The operator should remain in the operator compartment. The second person should remain on the ground.
Read this instruction carefully before you attempt to lower the bed with a dead engine. Locate the two valves that are described in Step 2 before performing any of the steps below. The secondary steering pump can only be operated for two minutes without risking damage to the pump motor.
- The operator places the hoist lever in the HOLD position.
- The person on the ground will find the manual valve under the machine's left, front fender. The knob (1) for this valve looks like a mushroom top. The person on the ground must also locate the three valve group. The valve group is located in the transmission's rear area. The valve that needs to be used is the smaller outermost valve (2). Loosen the locknut on the valve. Loosen the valve retainer 3 or 4 complete turns.
- Pull the mushroom topped knob upward. The mushroom topped valve is spring loaded. The mushroom topped valve will NOT remain in the OPEN position. Opening this valve will open an oil flow passage from the electric pump to the rod end of the hoist cylinders.
 | |
| Illustration 1 | g00417278 |
Mushroom Top Knob (1) | |
 | |
| Illustration 2 | g00417298 |
Three Valve Group (2) | |
- The operator should actuate the electric pump motor for the secondary steering. When the pump motor is ON the bed should lower in 40 to 45 seconds. If the bed moves too fast the valve retainer can be tightened 1 to 2 turns in order to regulate the oil flow from the head end that returns to the tank.
| NOTICE |
|---|
Do not operate the electric pump motor for more than 2 minutes at a time. The electric pump motor can OVERHEAT and DAMAGE the internal windings. |
- When the bed is lowered shut OFF the electric pump motor. Reset the valve from the three valve group to the original settings. Release the mushroom top knob.