Today I installed the JD horn kit BLV10359 on my 4066R with cab. I could not find it in the technical library, so maybe the admins might want to add it as it appears I am unable to do so myself.
The hardest part was getting the knobs off the 4WD lever and the throttle lever. The 4WD lever is flat and the throttle lever is round, but both pull straight off. However, both are very difficult to pull off, especially the 4WD lever. There is nothing in the instructions regarding how to remove the knobs. I used a claw hammer to pull them off. The entire dash must be removed and there are several electrical connections to disconnect. None are duplicate, so you cannot reconnect incorrectly. There is plenty of length on these connections, so you can pull the dash out quite a ways to be able to remove the connections easily. Be careful around the horn connections after installation as they are live all the time, meaning the horn can be honked without the key turned on.
1..Dash back before horn button installed..note the indentation where the hole is to be drilled. I did not have a 16mm bit, so used a 5/8 inch bit.
2..Dash back with horn button installed
3..Dash front with horn button fully installed.