OM3212 08/11 Operator Cab and Controls - Section 32 Page 32-3 Windshield Wiper / Washer Control The windshield wiper control is used to activate the wiper blades and washer system. This control is on the turn signal lever and has three wiper speed set- tings and a washer control: b. When the lever is rotated "downward" (clock- wise), it is in the ON/RETARD position. The ON position encompasses a full range of motion that allows a variable retarding effort depending on the position of the lever (and the potentiometer inside the assembly). As the lever is rotated further clockwise, more retarding effort will be applied. c.
For long downhill hauls, the lever may be positioned anywhere to provide the desired retarding effort. The lever will remain where it is positioned until moved. Refer to Retarder Operation in the previous chapter for cau- tions when using the retarder on a downhill grade. Rotate the knob on the end of the lever clockwise (from OFF position) to activate the various speed selections. OFF: Wipers are Off. When retarding is completed, and acceleration is resumed, return the lever to the full "up" ( OFF/NO RETARD ) position to prevent rapid wear to brake discs and/or overheating of the brake cooling system. Wipers operate at intermittent speed. Wipers operate at low speed.
The retarder lever and foot-operated service brake pedal can be used simultaneously or independently. The Retard Control Module (RCM) will determine which device is requesting the most retarding/braking effort and apply that amount. Wipers operate at high speed. Grasp the control knob and push in (toward steering column) to spray washer fluid onto the windshield. SERVICE BRAKE PEDAL Service brake pedal (3, Figure 32-1) is a single func- tion, foot-operated pedal which controls and modu- lates service brake pressure directly through a hydraulic valve.
RETARDER CONTROL LEVER When the pedal is partially depressed, an indicator light in the LH instrument panel pod (11, Figure 32-9) will illuminate. As the pedal is further depressed, the service brakes are actuated (a slight increase in pedal resistance will be felt) through a hydraulic valve, which modulates pressure to the service brakes. Completely depressing the pedal causes full application of both the front and rear oil disc service brakes. Retarder control lever (6, Figure 32-2) is mounted on the right side of the steering column. It can be used to modulate the full range of retarding/braking effort being applied to both the front and rear oil disc brakes.
Any application of the retarder lever will cause an indicator light to illuminate in the LH instru- ment panel/pod (Refer to Instrument Panel And Indi- cator Lights). a. When the lever is rotated to the full "up" (counterclockwise) position, it is in the OFF/ NO RETARD position. Retarding capacity chart (8, Figure 32-1) should always be followed to determine maximum safe truck speeds for descending various grades with a loaded truck.