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GMTechBernard, Shop Foreman - GM World Class Tech
Category: Chevy
Satisfied Customers: 2158
Experience:  GM
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1994 chevy s10: the location of the fuel pump regulator switch

Customer Question

the location of the fuel pump regulator switch for a 4.3 1994 chevy s10 or a late 1993 model
Submitted: 9 years ago.
Category: Chevy
Expert:  GMTechBernard replied 9 years ago.
Hello! Could you please be more specific as to what your looking for? The regulator and switch are two different things. What symptoms are you having and what are you trying to replace? Is this 4.3 Throttle Body Injected (looks like an electric carburetor) or is it Multi-Port fuel injected (large aluminum intake manifold on top)?
Customer: replied 9 years ago.
Its a 1994 Chevy S-10 4.3 Throttle Body Injection, fuel pump relay is what I`m searching for, in the book it says in front under instrument panel, forward of the center console, I`m looking but I`m not seeing it? Also its dated 12/93. Any clues?
Expert:  GMTechBernard replied 9 years ago.

It is under the dash, towads the center. Its mounted in a "conveinience center" (has all of your flasher relays and such).

You may need to pull some of the lower trim off to gain access to it.


Customer: replied 9 years ago.
I have the trim already pulled, I have the section you say is it, the relay next to the one you say is the Pump relay, are the same, and when switched nothing happens? Here is whats going on, I just bought the truck, not running, person who owned it said it needed a fuel pump, battery was dead at the time I got the truck, came home put it on a charger, and everything worked, fuel pump, everything. Started up and Ran Fantastic, even took it up the road, came back shut it off, and then it would not start again. Let it sit for a while, came back turn the key, and fuel pump came on, after this crazy noise under the dash, more than likely, from where we are at now. Replaced the Oil Pressure Sending unit, because for some reason they have a shut off thingy going on with it and the fuel pump{I know its in case the oil gets low, it shuts off the fuel pump}? Being that the pump was working, I`m hoping its the Relay, especially after that weird noise, and vibration in the dash? I even checked the fuel filter down by the tank, relieved the line pressure, and the pump, kept going, but now If I poor fuel in the TBI, then it will run. So its something to do with the Electrics somewhere? Peace Joe
Expert:  GMTechBernard replied 9 years ago.

I don't think the relay is going to fix your problem, because the oil pressure switch isn't to shut off the pump in case of oil loss, its supposed to allow the pump to run in case the relay goes bad, providing you have oil pressure. The oil pressure switch is a "back up" should the relay go bad.


Customer: replied 9 years ago.
Okay, if thats the case, then the relay must have gone bad a while ago? Plus if thats the case, what is the other relay next to the fuel pump relay?, They are Identical, so I changed then up, and yet still nothing, does this mean the other relay is bad also? So I changed the Oil Pressure switch also, and still nothing, thats why I was hoping it was the relays? So now I`m a bit more confused than before?
Expert:  GMTechBernard replied 9 years ago.

OK, look at this wiring diagram for your fuel pump:



If you look at the output for your relay, you will notice it has two wires, one to the pump and one splices into the wire from the oil pressure switch. So either component can operate the pump, both are not needed. If the switch fails, the relay will work the pump and if the relay fails, the switch will work the pump.

So if you put a new oil pressure switch in there, and the pump isn't getting voltage, then you have another issue, probably not the relay.

As far as whats next to the relay, I don't know off hand, but if you swapped it and it still didn't work, that further confirms that its probably not the relay. You either have a wiring issue somewhere or the fuel pump is bad. It is possible to have an intermittant fuel pump.