2000 S10 Blazer, 4DR, 4X4. Fuel Gauge is always on Empty and Fuel light is always on. So I read through the forums and discovered that the fuel level sending unit is a common problem on this model. Of course the sending unit is part of the pump assembly. So today I dropped the tank and installed a new pump assembley complete with sending unit. put it all back together, filled up with fuel and.....NOTHING! Gauge is still on E nd fuel light is still on.

Any suggestions? After all I have read it is highly unlikely that the gauge itself is bad (but possible). How should I test.

 

If the gauge reads empty, then the wiring is most likely disconnected at some point. I would trace out the wiring. You should be able to find a wiring diagram around here somewhere. If not, let me know and I'll see if I am better at looking.

 

OK so I did a little trouble shooting. I pulled the instrument cluster out and if I ground pin#1 of the fuel guage it goes to full (Low fuel light does not go out). This tells me the guage is most likely working. Here is the odd part I have a wiring diagram that says the wire from the sending unit is purple and goes directly to the guage. There are NO purple wires in the harness that connects to the cluster. Also when I test for continuity from the guage to the pins on the harness I get no continuity, the path stops at a little circuit board that I cant remove. Is it possible something in this little board is my problem?

So to help me troubleshoot a little more does anyone know the actual color of the fuel level sending wire that goes into the instrument cluster? Its not purple!

any other thoughts or suggestions are much appreciated.

 

I don't have the manuals here to tell you the pinouts, but I can tell you the sensor doesn't go to your cluster, it goes to the PCM (computer under your coolant tank). When you replaced the fuel pump sending unit did it come with a new plug for the wiring harness? If so replacing it might be a good idea. From the plug at the fuel tank to the computer that purple is a direct wire, there are no other disconnects. That ground is also supplied by the PCM, it's not connected to the chassis. (a bit of trivia). Assuming you dropped your tank out of the way enough to gain access to the plug...... (Careful of those pipes on the pump) if you either grounded or unhooked that purple your gauge would go to "E" Sending unit should read between 30-235 ohms resistance ranging E to F (within a few ohms)
I'll look for the info tomorrow for the PCM pins. I "think" they're in the red connector but you could check the PCM connectors for corrosion and if you're really bored slide that tank plug out above the frame and shove a 100 ohm resistor between the purple & black/wht. If your wiring is good the gauge will move up enough to turn the light off.
They're in the "CLR" connector (top right looking the the computer connectors) Looking at the connector with clip down: Fuel level sensor is pin 13 Bottom row of pins is 1-16 so 13 is four in from the right side. The sensor ground is pin 19. Top row of pins is 17-32 so 19 is three from the left If you put paper clips in the plug and check with a multimeter (don't try to push probes into it) you should "see" the resistance of your fuel sensor)
Good luck, been through two of 'em, and you can replace the sensor without replacing the entire fuel pump assembly. (never a bad idea to replace the pump as long as you're in there if it's a few years old)

 

Well, I wish I wish I wish I would have done more research before giving a certain used car lot my 6K! However, I am the proud owner of a 2000 4wd LT Blazer with 97K. That was 3 weeks ago. We are off to a rocky relationship. Two days ago, it left my wife and I on the side of the interstate, which led to an interesting ride home with a stinky tow truck driver and his barley legal "Co-pilot". We took the Blazer to a trusted known to us mechanic shop and they were able to find the problem quick. Go ahead and guess...I will wait. Fuel pump! So $597 later and two days after the repair, tonight I was driving home and got this orange glow inside the Blazer. Thats right kids..."Service Engine Soon" which is latin for I am about to leave your butt on the side of the road again. Auto Zone was kind enough to plug into the EKG machine of the vehicle and gave me a print out which said "Check fuel gauge sensor" and "Check all connections" also "Check fuel line connections". So, at 8 am I will be at th shop asking questions and letting them read the codes. My question? Simple...Is this just the start of the Blazers fuel issues or by replacing the fuel pump, will that help me avoid additional problems that seem to be common based on these threads? Note: I am within a 30 window of my purchase and I have one pissed off wife, so I am just looking for help from others that have or have had these fuel issues. Should I catch and release? Thanks

 

i just had the fuel pump in my 97 blazer- 4dr 4x4 replaced and now it seems as though the fuel gauge is kind of working backwards. The gauge shows empty when the ignition is turn on or it is running. Once the ignition is turned off then the gauge level starts to rise but only to the 1/4 tank mark. Any suggestions as to what could be causing this?

 

First of all, let me say sorry for not updating sooner. As promised I dropped my 2000 Blazer 4wd LT at my trusted local shop for the follow up repair. This after replacing the fuel pump the week before that. Well, after a day at the doc I felt good about things because the shop did not charge me anything! Said it was a vaccum hose (Dont know anymore than that). We drove the Blazer on a short in state road trip of about 300 miles RT. Ran fine, no problems (Even after a fill up). Today, is another story. The Blazer is having a sleep over at the same docs office for the same data code off the "Service engine soon" I had last week! So, to sum things up. I have had the vehicle for 30 days on Thursday, it has had a new fuel pump, new vaccum hose and is currently in limbo. If anyone is having or has had these type of fuel issues, I would love some input. At this point my next move is pay a visit to the car lot and play nice (For now) to see what they say. No one wants a vehicle with chronic problems. God Bless

 

I went through this and it was expensive! My fuel pump died, was replaced, and now my fuel guage "Waves" to me between 1/2 to 1/4 tank. When I accelerate, the gauge moves all the way PAST full to the far right peg. when I back off, the fuel gauge drops back to around where it should have been. After the level drops to 1/4 then the guage seems to read accurate again without all the "Wave"... Any ideas on this?

BIGGER_HAMMER

 

This may sound ridiculous and totally unrelated, but check your voltage at the battery, the alternator, and the junction box. I was having strange problems with my electrical, and the gas gauge would wave around whenever the turn signals were blinking, or when I pushed the brakes (lights go on) it would dip and wave before evening out...

I would also check the voltage at some fuses to see if there is a bad connection going to the fuse box. Check the gauges fuse while the truck is running. It should be the same voltage as at the batt/alt.

Doesn't cost you anything to check, and at least removes the possibility of weak power causing your troubles.

 

Got my blazer out of the shop for the 3rd time on Sat. Problem was a little black pressure sensor. No cost to me since it was replaced when they did the fuel pump 3 weeks ago and should have caught it on the 2nd visit. I put gas in it last night and set my trip. Lets see what happens...God Bless