The Remco 2154.A is a rate (speed) controller used with 12‑V diaphragm pumps in fertilizer and similar low‑volume applications. Common failures include blown fuses or tripped circuit breakers on the 15‑A/35‑A power feeds, damaged input wiring between the white (+) and green (–) controller leads and the pump’s red (+)/black (–) terminals, and board‑level component failure such as a burnt MOSFET or capacitor. First‑check steps: verify that the supply voltage is present at the controller terminals and that the fuse or breaker is intact; inspect all connections for corrosion or loose contacts; then test the controller’s output with a multimeter to confirm proper PWM signal delivery before proceeding to board diagnostics.[oss-gpt-20b]