2555 tac not working

[4020millj]

The tac is not working and I was wondering how to test the magnet? The wires are good as far as I can tell and the cab connection is clean and tight. Thanks

 

[deere4040]

 

[4020millj]

What book is that it doesn’t look like my JD one? Thanks I’ll try that!

 

[deere4040]

Tech manual for 23/2550.

 

[4020millj]

Mine is Jd 2355/2555 unless I can’t find it, it doesn’t have that part. Hopefully I can test it this week.

 

[Tx Jim]

Speed/hr meter sensor is located on LH front of timing gear cover.

 

[deere4040]

The test procedure is the the same for both series

Here is the speed sensor on my 2355

 

[4020millj]

Yes I cleaned the wire connections as best as I could before and no change.

 

[wore out]

Yes I cleaned the wire connections as best as I could before and no change.

I believe the most common failure is the circuit board behind the tach.

 

[Tx Jim]

Another thing to check is be sure wiring harness ground connections are good.