Fuel pump relays are responsible for turning on your fuel pump and shutting it down whenever you start your car. They are small box-shaped components covered in black plastic which have connectors sticking out of them (just like plugs) and they are connected to the ignition system of a car. Wiring them properly is therefore a very important task. Inappropriately wiring them may cause your car to have problems with starting and shutting off. Below are some tips on how to wire fuel pump relays correctly.
Before starting to wire your fuel pump relay, make sure that you follow all safety precautions first. Since you are dealing with electrical components, be sure to disconnect the battery in order to make sure that there is no electricity running through the system. Also remove the fuse of the fuel pump. No matter how simple the task may seem, remember that electricity is dangerous and that it can cause serious injury.
With regard to the electrical connections of the relay, be sure to label the wires as positive or negative. Most of the time, the red wire is positive and the black wire is negative. Interchanging the polarity of these wires could seriously damage your fuel pump or even the whole electrical system of the car. It may cause a short that would certainly not be beneficial to the health of your vehicle.
When you connect the positive and negative wires to the wiring harness going to your battery, make sure that the connections are secure and tight. Loose connections could cause irregular distribution of current which would keep your fuel pump from working its best. It would also generate heat at the area of the loose connections which could melt the connectors or the wiring, depending on the amount of heat produced.
4. Wire Gauges
Determine the correct wire gauge that has to be used for your fuel pump relays. A gauge is the thickness of the wire and its ability to sustain the amount of electric current passing through it. The smaller the gauge number, the thicker the wire. It is better that you use a thicker wire rather than a thinner wire when wiring your electrical components. If you are unsure as to what wire gauge to use, go for the thicker option just to be sure. Using a thinner wire for an application that requires a thicker one could cause it to melt because it cannot withstand the current passing through it.
5. Wiring Design
After you have successfully wired your fuel pump relays, there will be wires all over the place. Try to position the wires in such a way that they are not scattered all over your engine bay. Use clips and zip-ties in order to bundle the wires together so they are not hanging loose. Try to position them also in such a way that they are not too close to the hottest part of the engine to avoid them from melting. You should actually think of your final wiring design before you start wiring your fuel pump relays so you can determine the length of the wires that you have to use for the final layout.