No Power to Fuel Pump

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66fryder

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Hey all, Here is my problem. 2004 Dodge Ram 1500 5.7 HEMI... No power to the fuel pump.
Fuel pump is new, tested and is good. Relays have been tested and are fine, they also click when key is turned on. Fuse is good as well. New crank sensor. Ground at tank has been checked and ruled out. Continuity test if power wire from fuse box to plug at pump check out good. Replace relay with jumper wire (paperclip) truck runs like new with 58-60 psi on the rail. I am at a loss of what else it may be. HELP please!
 

justin13703

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How exactly did you test the relay?
 
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66fryder

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Jumper leads, 12 volt power source and ohm meter. Connect first lead from 12v positive to relay spade 85 & other lead from 12v negative to spade 86. Relay should click. With leads in place & ohm meter on continuity mode touch spades 30 & 87 with meter leads.
 

justin13703

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Damn good work lol that is the right way to test them. Most people just listen for a click and assume it works without actually testing continuity. But for some reason the relay is not getting the signal to latch through either pin 85 or 86, depending on if it is + or - controlled. I will have to see if I can find a diagram.

Do you have a chip in your key? Possibly the anti theft system is not letting the fuel pump turn on. I'm not completely familiar with the earlier 3rd gens like yours.
 
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66fryder

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Thank you sir... No chip in key
 

justin13703

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From the diagram that I found, it looks like the relay gets 12v to pin 85 when the key is in the start and run position. Then, pin 86 goes to the powertrain control module which controls the ground side of the relay to turn the pump on and off. So I would start by seeing if you have 12v at pin 85 with the ignition on. If not, it says that pin 85 is fed from ptc #1 which is basically a self resetting circuit breaker. If you have 12v at pin 85 with the ignition on, then your problem is on the ground side. Check for continuity between pin 85 and pin 37 on connector c3 at the powertrain control module. Also check the ground(s) for the powertrain control module itself. You can also check continuity between pin 86 and a good ground while someone turns the ignition on. You should get continuity there at least for a few seconds.
 
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66fryder

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Thanks for your help. After much wire tracing, it appears the issue was in the ignition switch. Installed new switch and BAM... we have the HEMI growling as she should be!!!
 

justin13703

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Sweet glad you got it running
 

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