Fuel pump fuse location

JAKEYBOY0998

MEMBER
1999 GMC SIERRA
V8
2WD
AUTOMATIC
230,000 MILES

Where would my fuel pump fuse be on my truck (5.3)? I have a new relay and fuel pump and it still will not cycle the fuel pump.

Saturday, November 27th, 2010 AT 3:56 AM

10 Replies

KEN L

MASTER CERTIFIED MECHANIC
47,602 POSTS

Hello,

ECM B fuse powers the fuel pump relay when the computer control of the relay coil energizes this is the time power will transfer to the fuel pump. Here is some diagrams (below) and guides to show you the location of the fuel pump fuse and to help you test the system and get it fixed.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Check out the diagrams (Below). Please let us know if you need anything else to get the problem fixed.

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Saturday, July 27th, 2019 AT 10:11 AM (Merged)

TERESAJ

MEMBER
3 POSTS

Ok my bad there was a bad fuse replaced it and now I have power on the orange wire to the relay. Now the switch that changes the tanks in the dash we think is bad. Bought a new one and you have to hold the switch down to make the fuel pump run - the old switch does the same thing.

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Saturday, July 27th, 2019 AT 10:11 AM (Merged)

SFCJDHERRERA

MEMBER
6 POSTS
2000 GMC SIERRA
V8
4WD
AUTOMATIC
130,000 MILES

The initial problem was having to turn the ignition over two to three times before starting. That went on for about a month before truck died on the road. I changed the fuel pump. I tried starting the truck with no susccess. After that I changed the fuel pump relay. Still nothing. I dropped the fuel tank again and checked for voltage to the pump. There was no voltage. I checked the relay to see if the relay was good. Yes it Is a good relay. The wiring schematics indiacate power should be coming from the PCM. That is where I am at. Stuck! Do I replace the PCM?

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Saturday, July 27th, 2019 AT 10:11 AM (Merged)

JDL

MECHANIC
16,098 POSTS

Welcome, thanks for the donation, did you check for voltage at the pump with engine cranking? Other than the initial prime, the pump won't run without rpm signal. You can pull relay, use teslite at relay terminals, see how many hot terminals, engine cranking. The load side of relay gets voltage from ecm b fuse. Voltage for coil side of relay does come from pcm.

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Saturday, July 27th, 2019 AT 10:11 AM (Merged)

KANT NGUYEN

MEMBER
6 POSTS
1995 GMC SIERRA
5.7L
V8
4WD
AUTOMATIC
200,000 MILES

Are the gray (86) and black/white (30) wires switched on the fuel pump relay circuit? Ive been trying to find this out everywhere! So, to clarify, the gray wire needs to be in the 30 position, right? Essentially moving the black/white wire to the 86 position? Or are they oriented correctly? I had to flip it to snap the pic so the fuel pump relay wires are in the top left corner. I am pretty sure that the other wires are correct. Any help would be greatly appreciated thank you

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Saturday, July 27th, 2019 AT 10:11 AM (Merged)

WRENCHTECH

MECHANIC
20,761 POSTS

No, pin 30 is the power supply coming into the relay on the orange wire. The gray wire is the power out to the fuel pump on pin 87. Pins 85 and 86 are the control wires that operate the relay.