2000 safari no power to fuel pump

So my work van died on me, wasn't getting fuel. Replaced fuel filter, which wasn't bad, but due for one. Thinking fuel pump went out, and for years the fuel sending was flaky, I just ordered a new fuel pump
assembly from Rock Auto. Ended up going with the cheap Startex after hearing from a couple people that AC Delco's were crap.
Pulled fuel tank, cleaned it out thoroughly, had to install the supplied electrical adapter for fuel pump and sending unit. Before installing the fuel tank, I hooked it up, turned the key on, couldn't hear the fuel pump, so I disconnected the harness and checked V at the harness, no power.
I then talked to a couple buds in IRC who suggested disconnecting battery, check ECM fuse, check if relay is getting power, and install the tank and put gas in it. Did all that, still no power to fuel pump.
Doing some searching for a wiring diagram (which I never found) I saw a few comments on forums relating to the circuit. One was computer gives power to the fuel pump relay for 2 seconds when starting, after that I'm assuming it routes power through an oil pressure switch.
So my problems are now: Fuel gauge reads dead empty (have 6 gallons in it) Quite possibly I have the sending unit wired backwards, although I was very careful in trying to get the supplied harness (4 wires, 2 for fuel pump, 2 for sending) wired correctly. I did solder the connections. And no power to the fuel pump.
Any suggestions?
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Yes, when you were testing with the tank dropped, did you have a good ground?
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You need the electrical diagrams which would be in a GM factory service manual set for your year vehicle (order from helminc.com), a multimeter, need to know how to read electrical diagrams and how to use a multimeter.
Otherwise take it to dealer for service.
"paulbot" wrote in message

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Thanks, Bill. I do have the factory service manual from Helm. Although trying to use it can sometimes be a pain. I've found the diagram, and have confirmed I have 12V constant at the relay, the ECM does provide 12V to the relay when key is turned on.
Turning key on, I get no power at the gray wire providing + to the fuel pump. Ground is good. Since the relay used for the fuel pump is the same as the AC relay, I swapped them out. Now I get 5V to the fuel pump. This indicates to me that there may be a short in the gray + wire. I pulled the relay and checked for continuity from the fuel pump feed to ground and found none.
To me this indicates bad relay (s), Only question I have is why didn't swapping identical relays solve the problem. If a new relay doesn't solve it, I'm looking at a break in the gray + wire to the fuel pump. Sound right?
It takes me a bit to get my head wrapped around electrical problems, I usually have to let it simmer on the back burner before getting a good mental picture. :-)
Paul
Bill wrote:

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paulbot wrote:

IIRC the Safari has a connector inline on the harness to the pump, seems like it was under the carpet near the front seat. Possible that you have a bad connection there. Been a while since I looked at the diagram but it should show it. Also it is possible that the relay socket is failing. Seen that happen when a pump starts to fail and draws more current than it should.
--
Steve W.

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Take you vehicle to a competent tech, who can properly diagnose the problem and have it corrected, WBMS

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