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June 26, 2026 Service bulletin

This bulletin describes the procedure to install a Grand Design RV – supplied diode into the water pump...

Grand Design technical service bulletin 26-004 for 2027 Grand Design Lineage.

Bulletin number
26-004 (26-004)
Component
Electrical system
Summary
This bulletin describes the procedure to install a Grand Design RV – supplied diode into the water pump control circuit of the Firefly Emprise electrical system on affected ProMaster LVP units. The diode prevents excessive current in the water pump control circuit that can damage the Firefly circuit board.

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