'93 White LWB, 235/85R16, 2" OME, Bottorf bumper, T-Max winch
Join Date: Apr 2010
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'93 LWB fuel pump relay keeps shutting "off"????
After replacing the fuel pump, filter, and relay in my ’93 LWB, I discovered that there was no power getting to the fuel pump. After checking the fuses and all circuits (inertia switch good, continuity from relay 87 post all the way to fuel pump-good), I discovered that the fuel pump relay itself was switching “off” after a few seconds being “on”. I removed the passenger seat so I could get a good look at it, and you can hear/feel it switch “on” when you turn the key on, but then it switches “off” after a few seconds.
I confirmed this with a circuit-tester; post 87 out of the relay sends power to the pump initially after key turns on, then relay clicks “off” along with power.
What can cause a relay to do this? I am beginning to suspect the ECU, which I think has a ground wire linked to this same relay.