[chuckv]

Ideal,

The battery charge voltage lamp on the 430 is only driven by the TDCM for some early tractors, but in others by the voltage regulator module itself. Here is the theory of operation description from the manual:

For (S.N. —420468):​

Battery discharge lamp (P3) warns the operator when​

battery voltage is low (battery voltage below​

specification). The battery discharge lamp DOES NOT​

monitor current output from the alternator.​

Battery discharge lamp controller (B) senses battery​

voltage present at fuse (F2). If the lamp controller​

senses low voltage (less than 12.3 volts), the lamp​

controller provides a path to ground for the battery​

discharge lamp. Since battery voltage is always​

available at the discharge lamp when the key switch​

is at the RUN position, the ground path provided by​

the lamp controller will allow battery current from fuse​

(F2) to flow through the battery discharge lamp and​

lamp controller, causing the discharge lamp to turn​

on. The discharge lamp will stay on until battery​

voltage increases to approximately 12.7 volts. At this​

point, the lamp controller will break the path to​

ground, turning the discharge lamp off.​

For (S.N. 420469— ):​

Battery discharge lamp (P3) warns the operator when​

alternator output is low. It DOES NOT monitor battery​

state of charge.​

When the engine is not operating and the key switch​

is in the RUN position, the regulator senses no​

current output from the alternator. In this state, the​

regulator provides a path to ground for the battery​

discharge lamp, turning the lamp on. During engine​

operation, the regulator will also provide a path to​

ground for the battery discharge lamp when current​

output is below specification (less than 12.3 volts).​

When the engine is operating and the alternator​

produces current output that’s over the minimum​

specification (approximately 12.7 volts), the regulator​

senses the current output and breaks the ground path​

to the discharge lamp, turning the lamp off.​

Note there are separate descriptions for the various serial number ranges... What is the SN of your machine?

Here is the wiring diagram:

Chuck