Auto Repair : How to Check a Fuel Pump Relay

A fuel pump relay's job is to take some of the voltage load off of the wiring harness to allow a better current flow from the battery to the fuel pump. Determine whether a fuel pump relay is bad and needs to be replaced with help from an auto mechanic in this free video on testing car performance.

Expert: J.B. Hebert
Contact: www.wrxtra.com
Bio: J.B. Hebert is a machinist, metal fabricator, and auto mechanic who has been fixing and modifying all things mechanical for over 20 years.
Filmmaker: David Pakman

Category:

Autos & Vehicles

Tags:

• auto
• repair
• car
• maintenance
• troubleshooting
• problems
• automotive
• repairs
• transmission
• capacitor

[10MickeyMouse]

Also, why don't you tell people which terminals to test? Most relays have 4 or 5 terminals, labeled 30, 85, 86 and 87 (plus 87a on a 5-pin). 85 & 86 are the control circuit, 30 and 87 the load circuits. And relays aren't meant to "take some of the load off"; Their purpose is allowing a low current circuit to control a high current circuit. Basically, they're mechanical power transistors.

[PaCPoD69]

5 stars, keyword how to test a Relay..

[10MickeyMouse]

@camarocomputer I know how to read a relay schematic, but not everyone does. THAT is why I suggested he explain the terminals. It's not for my benefit. And I don't need to guess with Google diagrams; I pay for Alldata. Trust me, Google will get you the wrong info more often than not in ths case. Good luck.

[hpwan2]

the repay found on my 1988 300E has about 8-9 pins......

[camarocomputer]

@10MickeyMouse he said which ones, Google a wire diagram of the car you're working on you lazy bum.

[sgtjasonshrout]

you have the ability on some relays to tear the cover off and clean up your contact points if they have fused. just wanted to put that out there. good vid!

[pbstar5640]

Sick wagovan in the backround

[koolguywow]

Also I check the fail safe switch under dash p/s kick panel the button was pushed in and as should be.,.. Ive already switch my relays around and obviously checked my fuses,.. Everything checks out proper

[koolguywow]

Yeah my 93 ford f150 isn't starting either I got it to start with starter fluid, so figured it was a fuel issue, jusy changed pumps less than a year ago, both front and back, I take down main front pump connect to 12v power supply, it runs, pump is good, I put it back run it off a switch I hooked up in cockpit to feed it a 12v power supply on command,.. Truck starts and idles fine with my set-up,.. But still doesn't answer the question of what is that original problem,.. Also I checked the e

[shotgunman4]

my fuel pump relay doesnt turn on when i turn on the key in my 1993 jeep grand cherokee laredo 4.0. i replaced the pump and relay so they are both good, i just dont know what to do. its starts off of oil pressure and im really lost! HELP ME, my starter is getting ready to take a shit

[NoleandertheGreat]

Not all relays use 12 volts for the coil. On computer controlled vehicles, which will apply to most people who landed here, the coils may use ~5 volts to produce a magnetic field to close the contacts. Check out my video on it.