1996 Chevy Suburban Fuel Pump Relay

Tiny
HCTUCKER
  • MEMBER
  • 1996 CHEVROLET SUBURBAN
  • V8
  • 2WD
  • AUTOMATIC
  • 143,000 MILES
What would cause the fuel pump relay to get power to be activated. The fuel pump relay has been tested and is good. There is no voltage to the #85 "terminal" or pin on the relay.

Also, there is a designated fuel pump fuse spot in the fuse box but no wiring to it.

Thank you for your help!
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Wednesday, May 13th, 2009 AT 10:13 PM

4 Replies

Tiny
DR LOOT
  • EXPERT
I'm assuming that your truck won't start right? And you have no power to the relay right? Have you tried sending power directly to #85"terminal"with a jumper wire? Answer my questions and I can probably help you.
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Saturday, May 16th, 2009 AT 3:39 PM
Tiny
HCTUCKER
  • MEMBER
Yes, we are able to bypass and the relay is good. The problem lies before that.
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Saturday, May 16th, 2009 AT 4:56 PM
Tiny
HCTUCKER
  • MEMBER
No, the truck will not start; it did briefly at one point and then sputtered off.

No power to the relay.
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Saturday, May 16th, 2009 AT 8:23 PM
Tiny
DR LOOT
  • EXPERT
Okay, this is really a little difficult but let's see if we can figure it out, I have done some extensive study to try to help you, first of all terminal #85 is the wrong terminal to test, it is terminal #87A, I have the Schematics in front of me I try to send it to you but the site will not support it, but because you knew about terminal #85 I will assume that you have the Schematic in front of you. Terminal 87A is the fuel pump test terminal, terminal #85 is the fuel pump relay control, terminal #86 is ground, and terminal #30 is power to the fuel pump, terminal #87 its power from the ECM, now that you know that you may have a bad computer not sending the signal to the fuel pump relay (which is power) but I don't think that's the problem, as I'm looking at the schematic I noticed that the oil pressure switch also gets its power from the fuel pump relay and the computer and that is because if you loose oil pressure the oil pressure switch will turn the power off to the fuel pump relay so you do not burn up the engine, so if I were you I would jump the oil pressure switch so it sends power to the fuel pump relay and if the vehicle stays on then you have a bad oil pressure switch if it doesn't make any difference then you have a bad signal from the computer which means you may have to replace the computer or other components I have giving you all the terminal numbers so now diagnose it and make sure you have power coming to the relay from the computer also power to the oil pressure switch terminal 87 and test the fuel pump again at terminal 87A let me know what happens.
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Sunday, May 17th, 2009 AT 11:36 AM

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