Polaris Quick Trim display on MFD - Trim speed, calibration, voltage effects

[K447]

For reference, here is info related to the Quick Trim indicator on the MFD display.

This video shows the rate at which the indicator moves full sweep from full down to full up position, then from full up to full down. You can just hear the click of the switch to begin the full down portion.

Note that there was no actual trim motor connected for this test. I used a 100 ohm resistor as the electrical load in place of the actual motor.

The MFD only responds to the voltage signals from the trim switches on the handlebar. The MFD does NOT receive a position signal from the actual motor. The MFD assumes the trim motor is moving at a speed that roughly matches the speed the display is changing.

Polaris made two versions of the 'Quick Trim' motor. There is a 'regular' version of the motor which takes about 7.5 seconds to move the trim nozzle from full up to full down or full down to full up position (14.0 volts battery).

Note: The Pro 785, Pro 1200 and 1999-2001 SLX models all have a 'fast' trim motor (6 RPM) which moves the trim nozzle in less time. The MFD used on these watercraft moves the display indicator at a faster rate to match the fast motor. If the trim motor and MFD are not of the same 'speed' then the display will not match the actual trim nozzle position.

Note that the MFD cannot know the actual nozzle position. It simply counts the amount of time you have pressed each button on the trim switch and moves the LCD indicator. The longer you hold the switch the farther the display moves.

If the display indication and the actual nozzle position do not match, there is a simple method to get them back into sync. Hold the trim switch in the full up or full down position until you hear clicks from the clutch inside the trim motor assembly. This is intentional and allows the trim nozzle to be held against the full up or full down position while the MFD display moves to also indicate full trim.

To calibrate the display to match the actual nozzle position:
Hold the trim switch until you hear the motor clicking and the MFD display has reached full indication for that direction.

Once calibrated, the display indication should be fairly close to correct, at least initially. Each time you press the trim buttons up or down the display and the actual nozzle position can get slightly more mismatched.

When you suspect there is excessive mismatch, recalibrate the display by holding the trim up or down until the display and the motor are both at maximum limit.

Note that the trim motor will only have electric power when the engine is running or you hold the Bilge button down (1997 and newer).

The MFD must not be 'sleeping' when you calibrate the trim indicator. Press the Mode button to wake up the MFD display if the engine is off and there has been no activity for more than five minutes.

This is with 14.0 volts battery voltage to the MFD.


Apparently the MFD adjusts its display speed as the battery voltage changes. The actual trim motor speed would of course change as the voltage feed to the motor changes. The motor will spin faster with a higher voltage and spin slower with a lower voltage.

The next video shows the MFD trim indicator taking about 9.3 seconds to sweep at 11.0 volts. Also shown is the MFD indicator sweep rate at 16 volts, takes about 6.3 seconds.

Note that the MFD can not accurately compensate for battery voltage unless the MFD's own voltage reading is correct. See this thread for calibrating the MFD voltage display.

[K447]

Building a test jig for the 8-pin Polaris MFD

For those who can read a schematic diagram and build a simple circuit, here is the test jig for testing a Polaris MFD.
See the attached PDF for a higher quality diagram.

This circuit allows workbench control of all MFD inputs and can test almost all operating modes of the MFD.

You can test;

• MFD power on (or wake up) - all LCD segments on test
• LCD digit clarity
• Tachometer display
• Voltage display
• Trim position indicator up and down and the rate of change
• Fuel level Full, Empty, Disconnected sender
• Oil level Full, Empty, Disconnected sender
• Engine HOT warning
• While the MFD is powered you can reset the Distance counter or the Engine Hour counter to zero.
• If the DC power is regulated to exactly 14.00 volts you can calibrate the MFD voltage reading for accurate display when installed in the watercraft

Note: The MFD speedometer uses an internal air pressure transducer connected to the small nipple on the back of the MFD shell.
If you want to test the speedometer you will need a source of compressed air with some control over the exact air pressure applied to the MFD air hose fitting.

There are five separate switches so it is best to build this into a small project box.

Note that the Trim Position switch is a momentary return-to-center-off switch just like the actual trim switch on the watercraft.




The AC voltage used for the simulated tachometer signal is not critical, but I would not use anything over 12 volts AC. The MFD tachometer input is quite sensitive, it does not need a big voltage swing to work. The tachometer reading will be ten times the input frequency in Hertz. 60Hz = 600 RPM. To ensure the MFD recognizes the RPM as that of a running engine it should be 1,000RPM or more.


I used a bridge rectifier to create a 120Hz full wave UNfiltered DC output (red waveform). The load resistor is necessary to ensure return to zero on each half cycle. This provides a reliable and stable 1200RPM reading on the MFD.

When the MFD is in sleep mode (more than five minutes of no activity) closing the RPM switch to feed the 120Hz tachometer signal wakes the MFD up just like starting the actual engine does.

See these related threads for ways to use this MFD test rig;

How to Reset the Engine Hour counter on the oval Polaris MFD display

How to reset and calibrate MFD voltage display for ACCURATE voltage readings

How to cut open a Polaris oval MFD to repair faded digits