Xenocron Fuel Pump Relay Kit Instructions, V3

***These are general instructions.  Take time to plan out this installation before you cut or install ANYTHING, as your installation may be different than the one outlined here.  Use of a voltmeter is recommended. Take note of the relay diagram below before you begin.***

Check out www.the12volt.com for more Relay information, it’s a great site for this kind of info.



Parts included: 

  • 12ft of 12AWG red wire
  • 2ft of 12AWG black wire
  • 2 “eyelet” terminals
  • 2 “spade” connector pairs
  • 3 large crimp connectors (relay)
  • 3 small crimp connectors (relay)
  • 2 small seals, 2 large seal, one plug
  • 1 relay with mount and retainer
  • 1 fuse holder, 25a fuse and 3 terminals





  1. Disconnect your battery. (usually the negative)
  2. Determine what power source you will be using for your fuel pump.  We recommend using either the positive terminal on your alternator or your battery.  Connect the large 12AWG red wire to this power source.  If applicable, use one of the included “eyelet” terminals.  Before connecting the other end of this wire, take note of whether you will need some of it to connect the fuel pump to the relay harness (see step 4).  If the relay and harness are mounted close to the pump, you may not need any additional wire.  You can now connect the 12AWG red wire to pin #30 on the relay using one of the large crimp connectors and large seal.  
  3. Cut off the plug on the end of the factory wiring to the fuel pump.  Connect the positive wire from the stock wiring to pin #85 on the relay using one of the small crimp connectors and seals. Connect the negative wire from the stock wiring to pin # 86 using one of the small crimp connectors and seals.  If you want to retain the factory connector without cutting it, use male spade crimp connectors (not included).
  4. Using the 12AWG black wire, you will now make a new ground for the pump.  On one end, crimp an “eye hook” connector onto the black wire and ground this to the chassis.  It is important you have a CLEAN chassis ground so you may need to ground down, paint or primer depending on your application.  Connect the other end of this black wire to your fuel pump negative.  Depending on your application, you may be able to use one of the included “spade connectors.”
  5. Reconnect your Battery
  6. To test (before hooking up the final wire to your fuel pump), most ECUs have a “priming” stage when you turn your key to the “ON” position.  Normally the pump will prime for 2 seconds and then shut off.  To test, hook a test light or voltmeter to pin #87 on the relay and see if you receive 12 volts when the ECU primes the pump.  If this is the case, you have hooked everything up correctly.  
  7. Hook up the Fuel Pump Positive wire to pin #87.  You can use left over 12awg red wire and the spade connectors here between the fuel pump hanger and the relay, or mount the relay as close as possible to the fuel pump hanger and use the factory wire keeping it as short as possible.

Here is what you should see when you open the package:

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