Two Blue Sea battery selectors can look similar at first glance yet use different cable terminals. The 11001 belongs to the e-Series, while the 11003 is an HD-Series switch. Both let a DC load group draw from battery bank 1 or bank 2 and both include alternator field disconnect (AFD) contacts. This guide makes the switching arrangement and the model-specific connection details easier to compare before ordering a replacement.
What OFF, 1 and 2 mean
Both 11001 and 11003 are three-position selectors. They have an OFF setting and separate selections for the two battery inputs. Unlike a four-position 1–2–BOTH–OFF selector, these models do not offer a BOTH/COMBINE setting.
OFF
Neither battery input is selected. The common switched output is isolated from both inputs.
Position 1
Bank 1 feeds the selected output; bank 2 is not connected through the switch.
Position 2
Bank 2 feeds the same output; bank 1 is not connected through the switch.
Identify the switch connections
When reading the Blue Sea connection drawings, look for these markings rather than assuming the rear studs are in the same physical position on another switch.
| Reference | Purpose | What to check |
|---|---|---|
| 1 | Battery input 1 | Positive connection for the first battery bank. |
| 2 | Battery input 2 | Positive connection for the second battery bank. |
| COMMON | Selected positive output | Feeds the load group from whichever bank is selected. |
| F1 / F2 | AFD auxiliary contacts | Used only when connected for a suitable alternator field-disconnect application according to Blue Sea's instructions; not load-current studs. |
11001 versus 11003: the useful differences
| Detail | 11001-BSS | 11003-BSS |
|---|---|---|
| Switch family | e-Series | HD-Series |
| Maximum DC voltage | 32V DC | 32V DC |
| Battery inputs / settings | 2 inputs; OFF, 1 or 2 | 2 inputs; OFF, 1 or 2 |
| Main terminal studs | 3/8 in–16 (M10) | 1/2 in (M12) |
| Alternator field disconnect | Included | Included |
| Battery combine position | Not included | Not included |
| Mounting | Surface or rear-panel | Surface or rear-panel |
Matching Blue Sea battery selector products
These are the exact 11001-BSS and 11003-BSS listings in NewRVParts, with their current catalog images. Open the product page for price and live warehouse availability; these parts are shipped rather than offered for in-person viewing or pickup.
Manufacturer diagrams and instructions
Blue Sea provides model-specific 11001 e-Series specifications and 11003 HD-Series specifications. For the actual rear-terminal layout and mounting drawings, refer to its 11001 installation sheet and 11003 installation sheet. Confirm the current instructions for the supplied revision before making electrical connections.