Some days i feel like i'm beating a dead horse

[echo7bravo]

I have scoured the internet over and still come up short when it comes to wiring for the fuel gauge in my '86 K-10.

I have found diagram after diagram on the wiring from the LH and RH fuel tanks to the selector switch.

What I am looking for is the path the wiring takes from the selector switch to the gauge it self. I have no continuity from the sending units to the gauge. So, my needle is pointing past fuel. I understand that if it was grounded out it would go to empty and that 88 ohms is the magic number for the FULL mark.

I have replace my selector switch. My truck is swapping from LH to RH and back just fine. I have checked the grounds on both tanks. But being that both tanks are not sending signal to the gauge.....It is my thought that the problem lays between the gauge and the tanks.

I appreciate any and all help!


Adam
echo7bravo

[echo7bravo]

I am wondering if maybe I need to pull my cluster and check all the connections and the printed circuit card. (as I think out loud)

I just inherited this truck and have just started chasing down the gremlins. I dropped a crate GM high performance engine and built 700R4 in it as well as rebuilt both axles from hub to hub. It runs stops and steers. But boy does it need electrical, interior and body work.

[Damien]

The fuel gauge on my '83 didn't work for either tank until i changed the valve. As soon as I plugged the new valve in the gauge started working again so it may just be a bad switching valve.

[echo7bravo]

Originally Posted by Damien

The fuel gauge on my '83 didn't work for either tank until i changed the valve. As soon as I plugged the new valve in the gauge started working again so it may just be a bad switching valve.

I pulled the gauge cluster out a little this afternoon to pop a couple new bulbs in. The plug on the back of the cluster came unplugged a little on the bottom side of the connector and the lights went haywire. I then pulled it back out a little and pressed the connection plug back in its spot. Now the oil pressure needle is all the way to the right side of the gauge like the fuel gauge. Makes me wonder about the printed circuit card.

I think after the bad weather over the coming days I will pull the entire gauge cluster out and clean everything and put it all back together.

[andyh1956]

Do your lights operate properly all the time?
Reason I ask I had a truck that the electrical would go haywire sometimes. Long story short the ground circuit from the dash cluster was bad. I spliced in a new ground to the wire in the dash cluster plug & grounded it on a steering column bolt & everthing went to work & has been working ever since.

[echo7bravo]

Originally Posted by andyh1956

Do your lights operate properly all the time?
Reason I ask I had a truck that the electrical would go haywire sometimes. Long story short the ground circuit from the dash cluster was bad. I spliced in a new ground to the wire in the dash cluster plug & grounded it on a steering column bolt & everthing went to work & has been working ever since.

I'm going to check that first. My dash lights are working as well as my turn signal indicators. And my oil pressure gauge was working yesterday prior to me pulling the cluster forward to change out cluster bulbs. I'm going to pull the whole cluster from the dash and clean everything and check the ground as see what happens.

[UPDATE]
I pulled my cluster out this evening. Took the gauges out and cleaned all the contacts. Took an eraser to the copper fins that lay across the overlay where the connector plugs in as well. Still nothing. Plugged it back in, turned the ignition on and the needles shot over to the right on both the oil pressure and the fuel gauges. Could the pinch connectors that connect the circuit card to the post on the gauges not be making good contact with the circuit card?

[echo7bravo]

Still chasing the fuel gauge gremlin. Everyone says check the ground on each of the tanks. It appears that the fuel sending unit is grounded to the tank just by contact being installed. I'm guessing the tank is grounded just by being strapped in. I can't find a ground wire anywhere.

There is one lead coming off of the sending unit and that is the pink wire that goes to the solenoid and then to the gauge. Any thoughts or ideas on the grounding of the tank?

[Danmcg]

There should be a ground wire from the sending unit to the frame.

found this pic online

[echo7bravo]

Originally Posted by Danmcg

There should be a ground wire from the sending unit to the frame.

So....a little on the back story is that the previous owner had this rig parked in the woods behind his house in lower Alabama. Rats had chewed through several wires under the hood to include spark plug wires. I'm thinking this may be the cause of why I have no signal to my fuel gauge. I thought I had found all of the broke (rat chewed) wiring. Now....I think otherwise.

[echo7bravo]

The question is now....How do I tackle this? With the old rusty bolts on the bed, I'm not ready to pull it off. I want to wait till spring when I replace the boards.

Perhaps I can get a new connector onto the sending unit using long needle nosed pliers. But I still can't figure out where the grounds attach to the tank/sending unit.

Nor can I figure out where the disconnect is on the RH Tank.

PUZZLED

[hatzie]

Wiring diagrams, by year, are in my signature.

Here's my dual tank theory of operation writeup. My intention was to demystify the NL2 dual tanks electrical operation.
http://67-72chevytrucks.com/vboard/s....php?p=8152326

Grounds depend on the model.
ALL 73-86 CK and 87-91 RV diesel models have a tang on the sender ring that GM used to attach a short pigtail ground to the frame. The original pigtail is a black wire with a non-insulated ring terminal on the frame to Non-insulated Flag terminal on the sender ring tang.


The 87-91 TBI RV series have an in-tank fuel pump with Ground, Pump Power, and sender wires running through a strain relief in the top of the sender. The ground is a ring terminal and the remaining wires are run through a Weatherpak.