Also I’m at the firehouse today so non of the suggestions can be implemented until tomorrow.
My pump is wired to the original lift pump harness.Usually the add on relay on the Gen3 is triggered from the OEM connector that is located to the rear of the fuel filter canister where the factory pump sat.
To use that wire to switch the relay is also important to get rid of the P0628 low voltage code.
A relay has always 2 circuits, the switch and the load. Apparently the power to the load side is ok on yours, but the switch side not.
On the relay itself only one of the 4 wires is a ground wire, the other 3 have positive power.
It was mentioned before, if you take the relay out of the circuit, and connect 30 and 87 direct, means hardwire. That means the wire runs straight from the battery to the pump without anything inbetween- does the pump then run?
Did you check the ground wire for the pump for continuity?
If you hard wired it - it must run, pop the fuse or just burn up.
One of this 3 will happen that way, IF the circuit is intact.
Just to make the relay configuration clear. If you look at the sketched drawing above, there is a common, normally closed (shelf state) and a Normally open (coil energized). Usually labeled C,NC,NO. In your case the red is on common, yellow on normally open. Nothing is going to happen until you can get 12vdc across the coil, black and tan on a good relay.
I have already swapped two brand new relays in with no change.
If you have power at the yellow the relay energized which is a good thing. If the pump did not run make sure the yellow has a good connection to the pump and the pump has a good ground. How is the relay coil wired now, to the battery or the ECM, the Tan wire. Which meter test ?
If you have power at the yellow the relay energized which is a good thing. If the pump did not run make sure the yellow has a good connection to the pump and the pump has a good ground. How is the relay coil wired now, to the battery or the ECM, the Tan wire. Which meter test ?
Meter set on appropriate DC range above 12vdc, Red probe to positive Tan in your case. Black probe to Black wire. If no reading check Tan to a known good ground, Battery etc. If no reading there is a problem with the Tan power source. For the ECM to energize (power) the relay coil bump the starter. You will have about 30 seconds to check power to the coil (Tan and Black). I am assuming since you now have power on the yellow that the Tan is connected to the Battery at this point ?.“troubleshoot with a meter. If no 12vdc across the Tan and Black the problem is elsewhere. Either no ground or no power.”
Meter set on appropriate DC range above 12vdc, Red probe to positive Tan in your case. Black probe to Black wire. If no reading check Tan to a known good ground, Battery etc. If no reading there is a problem with the Tan power source. For the ECM to energize (power) the relay coil bump the starter. You will have about 30 seconds to check power to the coil (Tan and Black). I am assuming since you now have power on the yellow that the Tan is connected to the Battery at this point ?.