M1009 Fuel Gauge Problem Fix

[camogriz]

My fuel gauge stopped working (stuck on full at about 3 o'clock) and it made me crazy trying to find the problem. Took out the tank, grounded the pink sending unit wire and then grounded the black ground wire from the sending unit. No movement from the gauge at all. Then I took the gauge out and replaced it with a working spare I had (I did this with the instrument cluster still installed in the dash, just removed the two plastic bezels and a few screws). Still no luck. I started looking for a broken wire somewhere, but could not find one and following the wire became difficult around the brake booster. I almost gave up, but couldn't think of anything else to try. Today I was tracing wires under the dash looking for my non-working horn problem and saw the wiring harness connector on the back of the instrument cluster looked strangely positioned. I reached up and pressed on it, apparently re-seating it in it's place and WOW! the fuel gauge started working again. It must have vibrated loose at some point. The strange thing was that everything else in the instrument cluster was working, leading me to believe it was just a fuel gauge system problem. By the way, it turned out that the horn itself had acquired just enough corrosion at the bolt hole on the radiator support to corrupt the ground circuit and keep it from working. A little sandpaper at that spot and my horn started working again. I hope my experience helps someone.

 

[Anubis8472]

Glad I saw this, I'll definitely have to check that connector while I'm at it.

Just a few days back my fuel gauge quit on me.
I had just topped it off the night before, then on the way to work in the morning I glanced down and it was reading 1/4 tank.
For a few miles I was livid, thinking that the teenagers hanging out at the house next door had overheard me mention to someone that I just filled it up, and tipped off thier buddies to come siphon it.
Few more miles down the road and the needle swung over to full, then after a minute or two, back down to 1/4.

Many times the problem turns out to be a bad ground at the sender, in this case it's droping down to 1/4 and seems to still move. From a little over 1/4 to a little under 1/4 as I burn fuel. My guess is that I need to replace the sender, but I'll be checking ground, sender wire, gauge, etc. first. I'll make sure to check that connector as well.

Anyone know off hand if the sender increases or decreases resistance as the float rises?

 

[Bamamastiff44]

I have replaced sending unit and fuel gauge, and it stays on empty! When I test the ground it goes to full, but once I replace the wiring in its proper place it does nothing! Could you give any other suggestions?!
Thanks

 

[Mike68]

This is what happened to me with my M1009 fuel gauge. I hope it will help someone else. Mine stuck at about 1/4 tank so I took it to my mechanic, Im not one when it gets past oil changes. Anyway He changed the sending unit in the tank and the gauge worked but it was moving all over the place. So I ordered a new gauge and after installing it, it works perfect. I did take the manual to him to trace down the problem and I we looked at the part where it said that if it shows about 1/4 tank its the gauge thats the problem. So the gauge may have been the problem and not the sending unit, I dont know. But at least I do know I have a new sending unit in the tank now.

 

[kipman]

Where did you get your gauge?

 

[Warthog]

Where did you get your gauge?

This is one place.

www.truckandcarshop.com

Page 43 of the 1973-1987 Chevy catalog.

Item # 82-34477 -$65

Or www.LMCTruck.com

Item # 36-1966 - $59.95

 

[Mike68]

I would have to look it up again. I will try to do that tonight. It was out of Ca.. I remember that. I think it was the first site warthog put up. I just typed in diesel fuel gauge for 1986 Blazer on ebay and found one. I didnt bid I called them because when you scroll down on their auction they had a contact #.

 

[Mike68]

I think I put 1986 Diesel K5 Chevy Blazer. sorry bout that. I think when I just put 1986 Blazer it brought up way to much stuff.

 

[Anubis8472]

This is what happened to me with my M1009 fuel gauge. I hope it will help someone else. Mine stuck at about 1/4 tank so I took it to my mechanic, Im not one when it gets past oil changes. Anyway He changed the sending unit in the tank and the gauge worked but it was moving all over the place. So I ordered a new gauge and after installing it, it works perfect. I did take the manual to him to trace down the problem and I we looked at the part where it said that if it shows about 1/4 tank its the gauge thats the problem. So the gauge may have been the problem and not the sending unit, I dont know. But at least I do know I have a new sending unit in the tank now.

Mine turned out to be a bad gauge as well.

After testing I determined I was getting all the proper ohms readings at the plugs behind the gauge.
After replacing the gauge it's working fine.

The only issue I have now is that my new-used gauge has a different level of sun fade. So the needles no longer match color wise. I though about replacing the needle with the old one. They just press onto the post, but in the end I decided not to risk screwing up the needle position.

 

[mich6212]

I replaced the guage in my Deuce when it was stuck at 1/4 tank, but now it reads past full all the time. I checked the wiring and everything seems good to go, but still incorrect readings. any ideas?

Oops, wrong forum, but hey if anyone knows please feel free. Thanks

 

[Mike68]

My needles dont match either with the new fuel gauge. The speed needle is faded. But Im just glad they both work now!!!