Skip the auto shop - Our mechanics make house calls

Q: What could cause fuse to keep blowing from fuel pump

asked by on

In April I replaced a fuel pump in my S10. When they replaced it , it blew a 20 amp fuse. They put in new fuse and it ran fine till this week. 5 months later. The fuel pump was bad and was replaced under warranty. It continues to blow fuse and they can't figure out what the problem is. Any suggestions?

My car has 160000 miles.
My car has an automatic transmission.

Fuses are over current protection devices which means that you either have a short to ground (possibly intermittent) somewhere in the circuit or enough added resistance in the circuit that the current drawn by the pump is enough to blow the fuse. You can use a volt ohmmeter to measure the current draw of the pump and see if it is within factory specified limits.

If you have a wiring problem, you can re-do (bypass) as much of the existing wiring as possible (i.e., re-wire the fuel pump circuit) because otherwise you will have to laboriously go over the entire circuit until you find the wiring fault.

You should also check to see whether the fuel pump is only device on the fused circuit. If not, check the other loads on the fuel pump circuit as those other loads could be causing the problem (the overload). To check that refer to wiring diagram in Factory Service Manual.

There is also the possibility of a physical (mechanical) restriction in the fuel pump tubing, filter and/or pick up causing the motor to overload and draw more current than intended. That’s why you should measure the actual current draw of the pump in normal operation to rule that out.

If you’re unable to perform these checks yourself, have a certified technician, like one from YourMechanic, come to you and diagnose the electrical problem firsthand for an accurate repair.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Truck is dead

Hi, do any lights come on in the dash? Which cables were changed as well? If there is nothing lighting up I would suspect a ground connection somewhere is loose. These can be easy to miss on a first inspection...

Q: Tbi problems

The fuel injector is a simple part. You can test the injector by giving it power and ground. If there is fuel pressure, it will spray for as long as you hold the power on. You can also check the...

Q: A/C light turns on

Hello there, thanks for writing in about your 2016 GMC Canyon. When the Air Conditioning Light is on like this, it is indicating that there is some fault in the system. When this occurs, it could be anything from a...

Related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...