Hobbs switch
09-23-2009, 06:30 AM
#4
First, you need to draw out a wiring diagram. Your Hobbs switch will only activate under boost, that is its function. It should be connected to a key-on source, just like an electric water pump. Look in your fuse box under the hood.
When under boost, the Hobbs switch should activate a relay, which then sends power to the second fuel pump. The relay is the device that should be connected to the alternator or battery, not the Hobbs switch. Also, there should be a fuse close to the alternator or battery (whichever you choose, I use the alternator) for safety.
See the first diagram for an EWP, and adapt for your application:http://www.ls1howto.com/index.php?article=26
Make a few mods. 12v source goes to the alternator, not the switchbox, and needs a fuse. Since the pump draws less than 10A, a 15A or 20A fuse should be fine. In place of the Meziere put your fuel pump. Switched trigger is the key-on 12v which goes to the Hobbs switch. The output of the Hobbs switch goes to 85.
Hope this helps.
**Please note, this is not the only way to do it, just the safe way and prevents running all the current through the Hobbs switch.**
When under boost, the Hobbs switch should activate a relay, which then sends power to the second fuel pump. The relay is the device that should be connected to the alternator or battery, not the Hobbs switch. Also, there should be a fuse close to the alternator or battery (whichever you choose, I use the alternator) for safety.
See the first diagram for an EWP, and adapt for your application:http://www.ls1howto.com/index.php?article=26
Make a few mods. 12v source goes to the alternator, not the switchbox, and needs a fuse. Since the pump draws less than 10A, a 15A or 20A fuse should be fine. In place of the Meziere put your fuel pump. Switched trigger is the key-on 12v which goes to the Hobbs switch. The output of the Hobbs switch goes to 85.
Hope this helps.
**Please note, this is not the only way to do it, just the safe way and prevents running all the current through the Hobbs switch.**
Last edited by koolaid_kid; 09-23-2009 at 06:35 AM.
