B2600 mazda fuel pump works when i jump it from battery but not from on 1990 Mazda B2600

Wiring harness, wiring harness is getting power, i plug them in, fuel pump doesn't work

Asked by for the 1990 Mazda B2600
ck fuel pump relay. how many volts are at fuel pump?
thx Globalhelper, i'll check it out & get back to u,how many volts should it b getting, again thx??
should be 12v to pump with key on
With relay off wiring harness 12 volts turn key on jumps to 10 volts
pull the relay and jump power at the relay connector, and see what happens, you could also bench test the relay and check the resitance is would tell you if you have bad contacts in the relay, does you mazada have fuel interia switch?
no switch, took old relay cover off, seemed to be working, maybe points worn a little, replaced with new relay, pickup ran for two blocks then dyed, won't start, thinking of putting fuel pump on toggle switch
check your ground side of the ciruit see if you cant take a volts meter put positve lead on power and put negative lead on the fuel pump circuit ground, cause if you have 12 volts at the pump it should work but if you have a bad ground it wont work, also make sure u r on the actural power wire for the pump and not the fuel level sender, also take in mind the engine has to be cranking for you to test for power at the pump the computer has to see engine speed before it turns on the fuel pump.
1 more answer
sounds like you have a ground issue. look for a croded or broke ground
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