Fuel Gauge past full

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Jtobe81

Junior Member
Joined
Sep 29, 2024
Posts
11
Reaction score
3
Location
las vegas
First Name
Justin
Truck Year
1981 Chevrolet
Truck Model
c-10
Engine Size
350
Fuel Gauge reads past full. I tested the gauge it is good and new. new sending unit and tested with the gauge. works normal when hooked up with leads. tested the circuit board with leads to the sending unit and gauge works normal. checked ground.

I am lost think i have done everything.
 

Dmack

Full Access Member
Joined
Mar 13, 2019
Posts
332
Reaction score
435
Location
Central OR
First Name
Dave
Truck Year
1983
Truck Model
K20
Engine Size
350
3 o'clock means you have an open circuit, like a broken wire, unplugged, etc. 9 o'clock means it's grounded somewhere.
 

Jtobe81

Junior Member
Joined
Sep 29, 2024
Posts
11
Reaction score
3
Location
las vegas
First Name
Justin
Truck Year
1981 Chevrolet
Truck Model
c-10
Engine Size
350
yeah i did the trouble shooting steps that i found on you tube from lmc, where you test the gauge using a battery and leads. the gauge and sending unit work normal when i have them hooked up with leads to a 12v battery. That was my last thought maybe a broken wire. looks like the wire is pink/red from the sending unit. trying to follow it back but cant find out where it goes into the cab.
 

Jtobe81

Junior Member
Joined
Sep 29, 2024
Posts
11
Reaction score
3
Location
las vegas
First Name
Justin
Truck Year
1981 Chevrolet
Truck Model
c-10
Engine Size
350
I traced the wiring from the sending unit on the single tank on the drivers side, its a pink/wht wire that runs across the frame to a 6 point connector. previous owner converted to single tank. there is no selector valve. The harness is not connected to anything. looks like they didn't complete the wiring?
 

Jgonick

Full Access Member
Joined
Jan 12, 2017
Posts
290
Reaction score
373
Location
West Texas
First Name
Joel
Truck Year
1985
Truck Model
K10
Engine Size
350
6 point connector.
should be a pink wire (pnk-30) coming off connector- that is the wire that should run to your gauge.
Single tank set up has pnk-30 running directly to the tank.
You must be registered for see images attach
 

Jtobe81

Junior Member
Joined
Sep 29, 2024
Posts
11
Reaction score
3
Location
las vegas
First Name
Justin
Truck Year
1981 Chevrolet
Truck Model
c-10
Engine Size
350
How do I bypass the old wiring from the second tank, and wire from the single tank sending unit to the gauge?
 

Jgonick

Full Access Member
Joined
Jan 12, 2017
Posts
290
Reaction score
373
Location
West Texas
First Name
Joel
Truck Year
1985
Truck Model
K10
Engine Size
350
How do I bypass the old wiring from the second tank, and wire from the single tank sending unit to the gauge?
If PNK-30 wire is there, just connect it to tank instead of PNK/WHT-930. There might even be the correct connector on PNK-30 (notice on diagram above-the little circle on the wire)

attachment shows location of PNK-30 on bulkhead- you could check to see if yours is there if you are not sure
 

Attachments

  • bulkhead.jpg
    bulkhead.jpg
    108.8 KB · Views: 22
Last edited:

Jgonick

Full Access Member
Joined
Jan 12, 2017
Posts
290
Reaction score
373
Location
West Texas
First Name
Joel
Truck Year
1985
Truck Model
K10
Engine Size
350
You must be registered for see images attach
 

Jtobe81

Junior Member
Joined
Sep 29, 2024
Posts
11
Reaction score
3
Location
las vegas
First Name
Justin
Truck Year
1981 Chevrolet
Truck Model
c-10
Engine Size
350
Here is some pics maybe give some idea. in picture one that connector that goes to nothing is the pink / wht wire they had connected to sending unit.
 

Attachments

  • IMG_7512.jpg
    IMG_7512.jpg
    138.8 KB · Views: 19
  • IMG_7506.jpg
    IMG_7506.jpg
    106.6 KB · Views: 19
  • IMG_7509.jpg
    IMG_7509.jpg
    177.1 KB · Views: 18
  • IMG_7514.jpg
    IMG_7514.jpg
    102.8 KB · Views: 19

Jgonick

Full Access Member
Joined
Jan 12, 2017
Posts
290
Reaction score
373
Location
West Texas
First Name
Joel
Truck Year
1985
Truck Model
K10
Engine Size
350
In theory- follow the pink wire (pnk-30) from 6 point connector- you should come across the same type of connector that is on the pnk/blk wire (the one you show in the attachment) - unplug it from the pnk wire running to 6 point connector and plug it into sender. - I believe it should reach the tank (hopefully)
 

Jtobe81

Junior Member
Joined
Sep 29, 2024
Posts
11
Reaction score
3
Location
las vegas
First Name
Justin
Truck Year
1981 Chevrolet
Truck Model
c-10
Engine Size
350
Ok I found the connector you were talking about, disconnected it, was too short so i had to extend it. plugged it into the tank. good sign its not past full to the 3 oclock anymore. cant remember on these trucks, the tank is about 1/2 full maybe little more. when i turn key on it goes to about 1/2 then when shut off climbs back to full.

Thx for your help! making progress
 

Jtobe81

Junior Member
Joined
Sep 29, 2024
Posts
11
Reaction score
3
Location
las vegas
First Name
Justin
Truck Year
1981 Chevrolet
Truck Model
c-10
Engine Size
350
weird now when i turn on the head lights the fuel gauge goes to 9 o'clock?
 

Latest posts

Forum statistics

Threads
44,102
Posts
949,400
Members
36,200
Latest member
cj7_hvn
Top