Fuel pump relay location and fuse

Tiny
FRENCHYTIME
  • MEMBER
  • 1999 CHEVROLET TAHOE
  • V8
  • 4WD
  • AUTOMATIC
  • 77,300 MILES
Where is the fuel pump relay located on a 99 tahoe?
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Tuesday, March 2nd, 2010 AT 3:39 PM

13 Replies

Tiny
DOCFIXIT
  • EXPERT
Hello,

Here is a guide to help you test the relay and the relay location is the diagrams below:

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Check out the diagrams (below). Please let us know if you need anything else to get the problem fixed.
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Tuesday, March 2nd, 2010 AT 3:42 PM
Tiny
DCKY320
  • MEMBER
  • 1999 CHEVROLET TAHOE
  • 5.7L
  • V8
  • 4WD
  • AUTOMATIC
  • 154,000 MILES
I got a 1999 Tahoe in non-running condition. Have since gotten it running and have been dealing with various problems along the way. My recent issue is with the fuel pump relay. I have actually had issues with it since I started working on the truck, but trying to solve the problem once and for all. The truck will work fine for a while could be a few days to a month or more. It will be working fine then out of the blue it will stop starting or I could even be driving down the road and it will shut down and not start. I narrowed the issue down to the fuel system when it has this issue and found the when this happens the #30 pin on my fuel pump relay will be burnt and the plastic at the base of the #30 pin will be melted. After this happens I replace the fuel pump relay with another one the truck will once again work fine. But there seems to be no pattern as to when or where this will happen. I have traced the wires and found no issues with them up to the gas tank. Would this be a symptom of a fuel pump going bad? Or is there an issue with something else in the system that I should be looking at? I have a 140 amp alternator on it and it generally runs between 14 and 14.5 volts but has gone as high as 15 volts when the weather was real cold for a short time, I have power everything on it, I had to replace the old 100 amp that was on it when I got the truck. I had the same issue with the relay back with the 100 amp alternator as well.
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Saturday, January 5th, 2019 AT 1:56 PM (Merged)
Tiny
HMAC300
  • EXPERT
This yea truck in particular has had fuel pump problems. The connector at pump and harness is bad and a new one with a different connector and about a foot of harness has to be installed. To save yourself grief go with delco, the whole part of harness and new connector should be included in the kit.
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Saturday, January 5th, 2019 AT 1:56 PM (Merged)
Tiny
BBLAND77
  • MEMBER
  • 1999 CHEVROLET TAHOE
1999 Chevy Tahoe Two Wheel Drive

Sometimes the fuel pump will kick on and sometimes it won't. I tried replacing the fuel filter and fuel pump relay. It will work one day and won't work the other. Every time I take it to a mechanic, it works fine. Then I get it home and it won't start the next day. Sounds like something electrical or some kind of sensor. It is just really annoying.
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Saturday, January 5th, 2019 AT 1:56 PM (Merged)
Tiny
RASMATAZ
  • MEMBER
Try powering the fuel pump direct from the battery and see what happens
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Saturday, January 5th, 2019 AT 1:56 PM (Merged)
Tiny
ALASKA_JULIENS
  • MEMBER
  • 1999 CHEVROLET TAHOE
Driving at hwy speeds and with no warning it died and as it happened I lookes at the gauges and they all went too the right then left except the fuel gauge. It remains stuck to right with the ignition on or off. On the side of the road the car would turn over just fine but wouldn't start. I"m suspecting the fuel pump or fuel pump relay. Your help is desperately needed!
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Saturday, January 5th, 2019 AT 1:56 PM (Merged)
Tiny
LEB
  • MEMBER
Why do you suspect the fuel system? Could it be electrical? Just thinking out loud.

It might be the pump, but my (all be it limited) experience is that the electric pump doesn't just die without some indication that it is failing. You may have symptoms like a hard start before it dies.

Have you put a fuel pressure gauge on it? If you measure the fuel pressure, it would be a good start in seeing what the problem is.
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Saturday, January 5th, 2019 AT 1:56 PM (Merged)
Tiny
TEAM TESTER
  • MEMBER
  • 1999 CHEVROLET TAHOE
  • V8
  • 4WD
  • AUTOMATIC
  • 130,000 MILES
I have a 99 Tahoe that I have replaced the fuel pump on at least three different times. Well this last time after I got it in, and turned the key over, it started popping fuses. It has never done this before after replacing the fuel pump. I am at a loss for what to do now.
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Saturday, January 5th, 2019 AT 1:57 PM (Merged)
Tiny
RASMATAZ
  • MEMBER
Hi Team Tester, Welcome to 2carpros and TY for the donation

Disconnect the fuel pump connector and see if it pops the fuse-let me know-
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Saturday, January 5th, 2019 AT 1:57 PM (Merged)
Tiny
TEAM TESTER
  • MEMBER
Okay, so we disconnected the relay and it blew the fuse still. So we disconnected the fuel pump itself and it still blew a fuse. Also now my fuel gauge in my dash is pointing straight down and doesn't move when the battery is disconnected and reconnected.

We have replaced the fuel pump 4 times now, and never had these issues before. We double checked the wiring going into the fuel pump and it is fine.

So now we are at a loss for what to do next. Any suggestions?
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Saturday, January 5th, 2019 AT 1:57 PM (Merged)
Tiny
RASMATAZ
  • MEMBER
The fuse you're talking about is it the Ign E 10amp?
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Saturday, January 5th, 2019 AT 1:57 PM (Merged)
Tiny
TEAM TESTER
  • MEMBER
No it's one of the 20 amp fuses.
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Saturday, January 5th, 2019 AT 1:57 PM (Merged)
Tiny
RASMATAZ
  • MEMBER
What is the fuse amp and what does it powers, you need a professional help here this can drag on if you're lacking electrical experience -let me know
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Saturday, January 5th, 2019 AT 1:57 PM (Merged)

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