Often you may come across the issue of the vehicle not starting or it stops suddenly when driving. These issues are typically connected to a problem with the fuel system components, especially the fuel pump which delivers the fuel to the engine that keeps the vehicle running.
The fuel pump is one of the most critical parts to keep the engine running. The failure or malfunction in the fuel pump leads to no fuel discharge to the engine which is necessary for its operation.
It happens that, people think the vehicle is not starting since the fuel pump might have gone bad, but often the car won’t start even after fuel pump replacement.
It becomes more difficult if the problem is not related to the fuel pump. There are several electrical components and wiring harness connections that ensure that the fuel pump gets power for its operation.
If one of the electrical parts gets damaged or malfunctions, the fuel pump won’t get power and it becomes time-consuming to identify the root cause of the fuel pump not getting power issues since the problem associated with the fuel pump can be related to more than one component.
In some cases, the fuel pump primes but no pressure is observed at the discharge line to the engine. This kind of issue is typically related to either the bad fuel pump or clogged fuel strainer and can be easily addressed by proper troubleshooting.
Whenever you are planning to change the fuel pump in your GM’s S10 vehicle, it is handy to know the S10 Fuel Pump Wire Colors to ensure that the correct wire gets connected to the right place to ensure the power supply to the fuel pump. Otherwise, your S10 truck won’t even crank.
The S10 fuel pump wire colors typically used are grey color for power to fuel pump, black and white strip represents a ground connection to pump, purple wire color indicates power to fuel level sending unit and black wire color signifies a ground connection to the fuel level gauge.
If you are interested in knowing the details of fuel pump wire colors in your S10 vehicle, then you are at the right place. Here, you will get to know everything you shall know while replacing the fuel pump. So, stay tuned!
Table Of Contents
Whats Are The S10 Fuel Pump Wire Colors?
The fuel pump module assembly usually comes with both the fuel pump and the fuel level sensor. Knowing which color wire is for which component helps in trouble-free fuel pump replacement.
Often, people are clueless about the wire colors and a good amount of time is required to spend doing iterations by connecting one wire after another to ensure that the fuel pump gets power supply from the battery.
Your S10 truck wiring harness may have color codes different from that of the new fuel pump assembly received for replacement and the problem starts when you mismatch the wiring connections and finally realize that the fuel pump is not even getting the required power supply.
Getting familiar with the wire color is important, if you are replacing the electrical connectors of the fuel pump since the one which is attached to the vehicle is different from that of the new fuel pump or the connector which is attached to the vehicle wiring harness has got damaged.
The fuel pump wiring harness usually has a color code. Some wires are signal wires and others either carry power or provide a ground connection to the circuit to ensure that the current flow through the fuel pump.
The typical S10 fuel pump wire colors used in GM vehicles are the grey, black and white strip, purple and black.
The grey color wire is meant to carry 12V current to the fuel pump, the black and white strip wire provides the ground path so that the current can flow across the fuel pump coils, and a purple wire is typically assigned to provide power supply to the fuel level sending unit and finally, a black colored wire ensures grounding of the fuel level sending unit wiring harness.
The GM fuel pump wire color codes are usually typical but there may be difference depending upon the vehicle model year.
What is the grey color wire on the S10 fuel pump?
The grey wire on the S10 fuel pump connects the fuel pump to the 12 V battery positive terminal. But this connection is not direct, then you may be wondering what sends power to the fuel pump.
The battery power source is connected to the fuel pump via. a fuel pump fuse, ECM main relay, ECM, and finally the fuel pump relay.
When you put the key to the ignition ON position, you activate the ECM main relay which sends the power supply to the ECM. This further activates the ECM to send ground signals to the fuel pump relay.
Once the fuel pump relay gets the grounding signal from the main ECM, the fuel pump relay circuit gets closed and finally, the fuel pump receives power supply through the fuel pump relay for 3 seconds and it stops running unless the key is turned to ‘START’ position.
Since there are several components involved before the fuel pump receives power supply, a malfunction in any of the parts or damage in the wiring harness will lead to no power supply condition to the fuel pump and the car won’t start even after the fuel pump replacement
What does the black and white strip wire on the S10 vehicle indicates?
The black and white strip wire on an S10 fuel pump typically provides a grounding path to the fuel pump power supply.
The grounding of the fuel pump is needed to ensure that the fuel pump receives power, otherwise, there will not be circuit continuity.
Using a multimeter, you can check the voltage across the fuel pump. Select the 20 V range in the multimeter and connect the positive lead to the fuel pump grey wire and connect the other lead to the black and white strip colored wire.
The multimeter shall read a 12 V power supply across the fuel pump. But if the multimeter shows no voltage, then there is no power supply to the fuel pump.
You can also check the resistance of the circuit by putting the multimeter in resistance mode.
If the circuit has no continuity, it will show infinite resistance and it indicates either a bad ground or a broken ground connection. It shall ideally show 0 ohms of resistance for a good ground connection.
What is the purple wire on S10 fuel pump?
The purple wire on the S10 fuel pump indicates a +5V power signal to the fuel gauge.
When you turn the ignition key to the ON position, the purple wire gets the power supply for the fuel level sensor which is a part of the fuel pump module.
As the fuel level increases inside the fuel tank, the fuel level sensor float gets lifted and the float lever rod traces a thin film resistor (TFR) circuit.
When the purple wire of the sender unit receives a power supply, due to the TFR film, it sends varying resistance values signal as input to the mechanical or digital arrangements on the dash panel.
What is the black wire on S10 fuel pump?
The black wire on a GM fuel pump designates a ground path connection to the fuel sending unit similar to what the black and white strip color wire provides to the fuel pump.
In a few vehicles, the fuel level gauge may have orange-colored wire instead of regular black wires. This depends on the vehicle model and year of manufacturing.
Final Thoughts
The S10 fuel pump wire colors help in easily replacing either the fuel pump or the wiring connectors.
The typical fuel pump wire colors used in your S10 truck used are grey and purple color codes for the fuel pump and fuel level sending unit power supply respectively, black white strips and black color codes for ground connection to the fuel pump and fuel level sending unit respectively.
If the fuel pump’s grey color or black wiring is done wrong then there are chances that the vehicle won’t start since the fuel pump won’t get a power supply, and it won’t discharge fuel to the engine for its operation.
If the fuel level sender unit’s purple or black and white strip wiring is done wrong then the fuel level indicator will show incorrect fuel level readings on the dash.
Hope the information will help you to avoid confusion while dealing with fuel pump replacement.
Happy motoring!
References
https://www.s10forum.com/threads/need-a-color-code-wire-diagram-for-the-fuel-pump.861329/
https://www.fixya.com/cars/t19270307-fuel_pump_wire_color
https://www.2carpros.com/questions/chevrolet-s-10-2003-chevy-s-10–39/page/2
https://www.camaros.net/threads/fuel-pump-wire-colors-help.41724/
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