Fuel Guage broken ?

[rich weyand]

That's a fuel tank selector valve, though not the same as the original, I think.
http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_x_3030229-P_x_x?cm_mmc=ACQ-_-Google-_-GPLA-_-3030229&ci_src=17588969&ci_sku=3030229&ci_gpa=pla&ci_kw=&gclid=CODApMG8sLsCFawRMwodLx4AVA#utm_source=acq&utm_medium=google&utm_campaign=gpla&utm_content=3030229

Here's what I think is the stock one.
http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_fuel-tank-selector-valve-acdelco_18051445-p?searchTerm=fuel+selector+valve

[darmentle]

So am about to say oh well and get an aftermarket cheap fuel gauge and see if that works.

[rich weyand]

Measure the ohms between the ground terminal on the gauge and the chassis, even better between the ground terminal of the gauge and the ground of the battery.  I'm pretty sure the problem is on the ground side of the gauge.

[darmentle]

do you know where the ground wire from the fuel gauge goes like where its bolted to does each gauge have there own ground .

[rich weyand]

Depends a bit on the year.  What year and model of truck is it?

[darmentle]

73 k20 4x4

[rich weyand]

Here's the pointer to all the manuals.
http://forum.73-87chevytrucks.com/smforum/index.php?topic=25639.msg213706#msg213706

From the pointers in that message, here's the wiring manual for your truck.
http://www.73-87chevytrucks.com/techinfo/7387CKMans//Wiring/X_7305_1973_GMC_Truck_Wiring_Manual_CK_10_30_Pgs_Only.pdf

The ground from the instrument cluster is the wire at the lower left of the connector (also lower left as mounted in the truck) labeled 20B-150B.  The "B" in "20B" stands for black, so that should be a black wire (BRN is brown, LBL is light blue, DBL is dark blue).  As shown, it immediately goes to a 4-wire splice behind the dash.  One of those wires, labeled 20B-150A, goes to a sheet metal ground.  Find the splice, check it.  Find the sheet metal ground, check it.

[darmentle]

I got it working i had to install a aftermarket gauge thanks for your guys help.

[rich weyand]

How weird.  Broken ground wire inside the gauge maybe?  From tests it seemed like the gauge was good.

Anyway, you got it, so that's good.  Thanks for letting us know.

[darmentle]

Well there was two issue going on . The ground was fine the first problem was that the wire for the sending unit wasn't sending a signal at the gauge cluster. I tested the the  connection at the cluster and i was getting no ohms there. So i followed my sending wire to the out side junction at the fire wall and tested it 84 ohms i had little less then a full tank so it was correct. So i ran a jumper wire from the wire at the junction to my OEM fuel gauge and it was still having a problem. So i just hooked up the aftermarket gauge.

[rich weyand]

By aftermarket gauge, was it a direct replacement gauge for the OEM?

[Boone83K10]

that fuel selector is correct for your year. Well you narrowed the problem down to inside the dash. how did you wire up the aftermarket? you obviously had to go outside the cab or else is should not have worked either if you spliced into it in the dash.

well if your jumper wire didn't work then it is the gauge.

[darmentle]

i just bought a cheap aftermarket gauge little 2" one from orielys for now. i was getting signal on the inside the cab at the fire wall so i ran the wire there. for now i am gonna run like that until i can find a working OEM in gauge  then i will pull out the whole gauge cluster and fix it right.

[rich weyand]

http://www.classicparts.com/Gauges-Switches/products/1012/

[darmentle]

Sweet thanks again 50 Bucks  for a fuel gauge is good deal and knowing that its working is a even better