Question about 1988 GMC Safari
Are you getting the ignition activated voltage to the relay? If you are, and you can jump across the relay to turn on the pump, I would say your relay is defective. If you know the relay pins for the ignition input and ground, you should be able to test it outside its plug in socket. You should hear it click when +12V and ground are applied to the proper pins/connectors for the ignition voltage. An ohm meter could be put across the supply +12V and fuel pump pins/connectors to really check the operation. If you think your relay is good. I would start checking for a bad +12V connection for your ignition supply, as well as the +12V that is switched through the relay. And the grounds to all. Use some contact cleaner on relay pins and socket. Ignition switch contacts can cause issues too. If it stays broke at least it should be easier to find than something that is intermittent. Based on what you stated, most of your troubleshooting should be at the relay socket (knowing which connectors do what) to isolate the issue to the relay, your ignition voltage, or your fuel pump voltage. After that it is knowing which step to take next.
Posted on Mar 02, 2015
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