Inertia switch wiring-Need relay?

[hammer189]

Putting in painless harness. FI Tech EFI. Have WH 23 gal tank with in tank pump and Ford fuel pump inertia switch.
Do I need to wire in a relay or just run the inertia switch in-line to the EFI fuel pump?
switch has 3 wires. C, NC and NO

Thanks, David

 

[Broncobowsher]

They have always been inline on all the stuff I worked on. No relay.
C is Common
NO is Normally Open
NC is Normally Closed

Common and normally closed should have continuity unless the switch is tripped.

 

[hammer189]

Thanks for the quick reply.
David

 

[Steve83]

This shows the best way to wire it:


(phone app link)

 

[englewoodcowboy]

The wiring that comes with the factory switch is light duty so I run them through a relay. I wire the fitch through the switch to trigger the relay in the aftermarket fuse panel. If it doesn't have one I add it. I have had the wires get very hot on the inertia switch and had 2 factory installs on a crown vic and ranger both fail by burning out the switch due to over load. Most likely the pumps were on their way out causing the extra amperage but on the broncos I don't take any necessary risks and run them through a relay. Only downfall of doing it this way is you can no longer slow down the pump but for an in tank install its not noticeable.

 

[hammer189]

Thanks for all the info. i decided to wire it using a relay for reliability/safety.
David