The Electric Pump Driver (EPD) has the task of allocating power to the electric pumps. To do so, the EPD must have an adequate power supply as well as a good communication line from the rate controller. This EPD operates on a PWM signal (Pulse Width Modulation) from the rate controller. As the intensity of the PWM signal increases, the EPD allocates more power to the pumps, thus increasing pump speed and output. Likewise, the opposite is true. When over applying, the rate controller lessens the PWM signal, thus slowing the pumps and their output. The attached documents explain the logic behind the lights on the Pump Driver (EPD). The most common symptom displayed by an EPD is a low input power warning (4 quick blinks, pause, 4 quick blinks...). As stated before, it is important that the EPD has a good supply of voltage in which to allocate. If the supply of voltage is interrupted or lessened, the EPD will show this warning. Causes of this can be loose, dirty or corroded connections (often at the hitch), poor connection at the tractor battery, damaged wire, or poorly seated fuse. CONTINUING TO RUN AN EPD WITH INSUFFICIENT POWER WILL CAUSE IRREVERSIBLE DAMAGE!
1) check all connections from the EPD to the tractor battery and replace any that look to have gotten hot, are corroded, or show signs of wear.
2) inspect the power harness for damage. If damage is found, solder the connection and heat shrink the repair. Crimp connectors will fail again!
3) check the connection at the tractor battery. CONNECTING TO A CONVENIENCE PLUG IN THE CAB IS NOT SUFFICIENT! Clean the battery terminals and replace the ring terminals if necessary
4) Check tractor voltage. A weak battery or poor alternator may cause low voltage issues
5) If the above repairs don't correct the problem, the EPD may have been damaged beyond repair. Replace the the EPD
Another common issue reported by the EPD is overcurent (two blinks, pause, two blinks). The most common reason for this fault is a failing pump. Pumps that begin to draw excessive current will cause this status.
