Fuel pump relay, no power to orange wire on relay?

1989 CHEVROLET SUBURBAN
100,000 MILES • 5.7L • V8 • 4WD • AUTOMATIC
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JEFF HERMAN
No power to orange wire on relay. Tracing this wire back to the junction block on the firewall side there's continuity through but the wire doesn't appear to connect to the under dash fuse block but rather joins into a loom that heads back, possibly to the ignition switch. Does this wire get its power from the switch? There's power to all the fuses under dash except ecmb, horn, tl/ctsy, instr. LPS. There's also no voltage to the either orange wire labeled batt. in the upper left of the block. This is a crank, no start but if fuel is poured in the TBI it starts right up. Can't hear fuel pump prime and when power is supplied to the short red test wire on the relay the pump doesn't run. Continuity tests through all fusible links and main grounds are clean and tight.
Sep 7, 2025 at 6:00 PM
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STRAILER
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Hi Jeff, So there is an oil pressure switch that maybe bad or the engine does not oil pressure. Here is the wiring diagram so you can trace the wires and test for power loss. Check out the images (below). Let us know how it goes
Sep 8, 2025 at 11:38 AM
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JEFF HERMAN
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I'll start with the pressure switch. Of course one of the distributor cap bolts broke which wouldn't be such a big deal if this wasn't a long distance project , as in 300 miles from home in the UP of Michigan at my cabins. Probably won't get to it until spring now. Dumb place to put the switch under the distributor if you ask me. Might have to lift it out of the way but we'll see. Any tips would be appreciated.
Sep 8, 2025 at 5:13 PM
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STRAILER
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Yep, that is in a tough spot for sure, you can remove the wiring connector and jump it to see if it makes any changes.
Sep 8, 2025 at 6:09 PM
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JEFF HERMAN
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Three wires to the switch, which ones do I jumper?
Sep 9, 2025 at 12:09 PM
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STRAILER
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Hmm, according to the wiring diagram there is two? Make sure it is not the oil pressure sender which is different than the switch.
Sep 9, 2025 at 5:03 PM
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JEFF HERMAN
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Dumb question but where's the switch supposed to be? Limited signal up here to do research.
Sep 9, 2025 at 6:42 PM
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STRAILER
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It is down by the oil filter, here is the location. Check out the images (below). Let us know how it goes
Sep 10, 2025 at 9:56 AM
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