2007 5.7 hemi fuel pump/sending unit

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.


Junior Member
Apr 12, 2024
Reaction score
Evansville indiana
Ram Year
5.7 hemi
Hello everyone,
This is my first time posting here. This is going to be a long read but im in some dire need of help.

A few days ago my truck died while driving. No warning, just boom. I scanned for codes and only have code for an o2 sensor that has been there for a year. I turned key and didn't hear fuel pump running, so I hit the bottom of the tank with my fist and it kicked on for a few seconds and died again. So naturally I assumed it was the fuel pump. I got towed to my work and in lunch I went to AutoZone and got a new fuel pump. I bring it back, get it put in and before reinstalling the tank I wanted to make sure that it worked. Turn the key and nothing. Got a test light and did some probing and found I wasn't getting power to my fuel pump. So then I start thinking fuel relay, and since it's integrated I know I'd have to buy a new tipm. After doing some more probing and testing I determined I had a bad wire somewhere behind my battery. I decided to do the bypass and ran a jumper wire and ran a new wire all the way to the pump, spliced into the harness for direct power. I plugged it into the pump and the pump still wouldn't come on. So I cut my sending unit wire at the pump and spliced it into my fuel pump wire and it worked, however I had no fuel gauge. I got a used tipm from a local junkyard today. I did a t-tap into the fuel pump wire just after the tipm and still had the same issues. So I decided to check out the pump to see if anything was messed up there and unfortunately the 4 wires were not soldered and had come out. So I tried my old pump to see if it would still work and when I plugged it in, it ran constantly even with key off. I'm just at such a loss with this thing right now.

Here are my questions.
1) when I put a test light to the sending unit pin on the tipm, should my test light light up?
2) does the sending unit wire act as a signal wire to tell the pump when to turn on and off?
3) what would cause my fuel pump to run even with key off?

I apologize for the long story, just want to give as many details as possible as to what I've tried. Hopefully someone can help me and point me in the right direction. Thanks for your time


Senior Member
May 28, 2020
Reaction score
Central Valley
Ram Year
when I had issues with an intermittent fuel pump, took some time to figure out but ended up being a frayed/broken wire under the driver side of truck, just aft of firewall. I’ve seen a couple others on here with the same issue since, so this would be a good place to check based on your symptoms.