Hey folks, I thought I'd document how to replace the solenoid for the chassis battery disconnect. A Dealer wanted to charge me 3.5 hours of labor to replace this $50 part at $130 per hour!! I decided to do it myself and save the $450 bucks. My solenoid was a Master Electronic Controls model NI-4412A. My Battery Control Center is RV Custom Products FW2050.
Temporary Bypass of Solenoid.
You can temporarily bypass the solenoid by:
1. Disconnect Chassis Battery terminals
2. Disconnect the cable on the side of the Control Panel marked “Chassis Switch” and connecting it to the cable connection marked “Chassis Battery”.
3. Reconnect Battery cables
This will bypass the solenoid completely, but your chassis will now have battery power always, with no way to disconnect, unless you disconnect at the battery.
Replacement Steps:
1. Disconnect both chassis and Coach batteries.
2. Remove Battery Control Center panel cover
3. Take LOTS of pictures showing how the cabling is connected and how the lines are connected.
4. Remove screws and bolts holding Circuit Panel in place.
5. Remove wires accordingly and mark wires with tape and identification where they go.
6. Carefully slide Circuit panel down – do not pull on it, as there are two wires that are soldered onto the backside of the circuit board that connect to the solenoid. With the Circuit panel hanging down, disconnect the two solenoid wires from the solenoid (note how they are connected).
7. Once solenoid wires are disconnected, circuit board can be removed completely and set aside.
8. Disconnect Buss bar holding in the solenoid and remove solenoid.
9. Repeat steps in reverse order to replace.
Good luck and happy RVing!
