Compass does not work show's south when heading north

question edited for clarity, (make model (what it is)'.

It appears to be a South African make. We are in North America, so this link may work better for you. There is also a link to the Barrington Diesel Club.

https://www.google.com/search?q=zetor+5745+head+bolt+torque+specs

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It is picking up a magnetic field from the phone and pointing in that direction. Something everyone learns in science class.

Hi Roger, I'm glad to help. Below is the procedure for resetting the compass on your vehicle.



COMPASS VARIATION ADJUSTMENT Compass variance, also known as magnetic declination, is the difference in angle between magnetic north and true geographic north. In some geographic locations, the difference between magnetic and geographic north is great enough to cause the compass to give false readings. If this problem occurs, the compass variance setting may need to be changed.
To set the compass variance:

1. Using the Variance Settings map, find your geographic location and note the zone number Figure 1.
Figure 1 - Variance Settings 2. Turn the ignition switch to the On position. If the compass/thermometer data is not currently being displayed, momentarily depress and release the C/T push button to reach the compass/thermometer display. 3. On Electronic Vehicle Information Center (EVIC) and Compass Mini-Trip Computer (CMTC) equipped vehicles depress the Reset push button and hold the button down until "VAR = XX" appears in the display. This takes about five seconds. On Compass Temperature Module (CT) equipped vehicles depress the C/T push button and US/M push button down until "VAR = XX" appears in the display. This takes about five seconds. 4. Release the push button(s). "VAR =XX " will remain in the display. "XX" equals the current variance zone setting. 5. On Electronic Vehicle Information Center (EVIC) and Compass Mini-Trip Computer (CMTC) equipped vehicles momentarily depress and release the STEP button to step through the zone numbers, until the zone number for your geographic location appears in the display. On Compass Temperature Module (CT) equipped vehicles depress the US/M push button to step through the zone numbers, until the zone number for your geographic location appears in the display. 6. On Electronic Vehicle Information Center (EVIC) and Compass Mini-Trip Computer (CMTC) equipped vehicles momentarily depress and release the RESET push button to enter the displayed zone number into the EVIC/CMTC module memory. On Compass Temperature Module (CT) equipped vehicles depress the C/T push button to enter the displayed zone number into the electronic module memory. 7. Confirm that the correct directions are now indicated by the compass.

Yes. Wish I could tell you which button for sure, but to reprogram the Compass you hold one of the buttons and drive in a circle one or two times to reacquire your position.

A field magnetic can cause that, or the circuit is not working.

the touch screen on the car should allow you to change the compass setting...I cant remmeber if yours has this but see if you can touch the compass on the screen display to make the direction allow of the car be in accordance with the cars real movement or north as you wish..Keep me posted

Compass Calibration
Before calibrating the compass, drive the vehicle to an area that is magnetically clean or free of large metallic objects. Verify there are no magnetized objects on the inside or outside of the vehicle close to the mirror.

Start the engine.
Press and hold the switch for the compass, which may be depicted as COMP, COMPASS, or On/Off (w/UE1) depending on the type of mirror on the vehicle, until the letter "C" or "CAL" is displayed.
Drive the vehicle in circles at a speed of less than 8 km/h (5 mph) until the "C" or "CAL" is replaced by a proper vehicle heading. The calibration procedure is now complete.
Compass Magnetic Variation Adjustment
Magnetic variation adjustments are required when the compass displays a constant error in heading. Variation is the difference between magnetic north and true north due to geographical location.

Try the following;

Compass Calibration
Before calibrating the compass, drive the vehicle to an area that is magnetically clean or free of large metallic objects. Verify there are no magnetized objects on the inside or outside of the vehicle close to the mirror.

Start the engine.
Press and hold the switch for the compass, which may be depicted as COMP, COMPASS, or On/Off (w/UE1) depending on the type of mirror on the vehicle, until the letter "C" or "CAL" is displayed.
Drive the vehicle in circles at a speed of less than 8 km/h (5 mph) until the "C" or "CAL" is replaced by a proper vehicle heading. The calibration procedure is now complete.
Compass Magnetic Variation Adjustment
Magnetic variation adjustments are required when the compass displays a constant error in heading. Variation is the difference between magnetic north and true north due to geographical location.

sounds like you need to adjust the compass zone-instructions should be in your owners manual

The "OC" indicates your compass is "Out of Calibration". Below is the proceedure to recalibrate your compass.

Compass Calibration
The compass may need calibration if:

After five seconds, the display does not show a
compass heading (N for North, for example), there
may be a strong magnetic field interfering with the
compass. Such interference may be caused by a
magnetic antenna mount, magnetic note pad holder
or a similar magnetic item.

The compass does not display the correct heading
and the compass zone variance is set correctly.
In order to calibrate, the letters CAL must be displayed
in the mirror compass windows. If CAL is not
displayed, push in the COMP button for approximately
eight seconds or until the letters CAL are displayed.
The compass can be calibrated in one of two ways:

Drive the vehicle in circles at 5 mph (8 km/h) or less
until the display reads a direction, or

drive the vehicle on your everyday routine and after
several turns the compass will become calibrated and
will display a direction.

Good luck.