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Trim guage testing

R

Rich Fan

New member
Can anyone tell me how to test to see if my trim guage is bad or if the sending unit has gone bad? This is for a 1989 Evinrude 175 hp outboard.
 
Assuming you have voltage applied to it and a good ground..... simply ground out the "S" (sensor) terminal of the gauge. If the gauge is okay, that will cause the needle of the gauge to pin in the full up position.
 
How to test a teleflex TT gauge:
Power the gauge by connecting a positive wire to the "I" terminal and a ground wire to the "G" terminal. Have no other wires connected to the gauge. Pointer should read full DOWN for Johnson/Evinrude engines. Next, with the power still connected, short the sender terminal at the gauge to ground. Pointer should go to the full UP position for Johnson/Evinrude engines.
How to test the sender (Johnson/Evinrude):
1. Locate the three pin connector for the trim control harness between the instrument and engine trim harness- you should see the white/tan lead from the sender and the blue/white and green/white motor control circuit wires.
2. With key switch OFF, connect a DVOM (set to read resistance) between the white/tan wire/terminal C of the 3-pin connector) and a good engine ground.
3. With the engine in the full down TRIM position, the meter must show a reading above 80 ohms.
4. With the engine in the full up TRIM position, the meter must show a reading below 10ohms.
5. If the readings differ, the sender must be replaced. If the readings are in the appropriate ranges, check the gauge.
 
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