Dash lights help

[Kevinn]

I have 1970 c10 396 bbc 1/2 ton and was trying to figure out why my dash lights dont work and my fuel gauge and I stumbled on this black wire with a blub not connected to anything and was wondering if need to be connected somewhere and if that's the cause why my gauge lights dont work. Also notice this grey wire with something on it dont know its for.I'll appreciate the feedback. P.s I'm new to this its my first car and learning bout this truck.

[DA71Grande]

The first one is the shift indicator bulb it plugs into the back of the cluster the second pic looks like it’s for your heater control bulb

[randy500]

Your dash lights probably don't work because the headlights switch is probably bad, there is a variable resistor (would wire) visible where it mounts, it provides dash light dimmer function, they go bad and or have bad spots.
Fuel gauge is probably the sending unit or float.

If the gauge goes to or sits at 3 o clock, the gauge probably has power and ground.
The tan fuel gauge wire at the fuse box upper right could have come loose or the wire on the sending unit could have come loose. Unhooking it and or plugging it in should make the gauge move, if it goes to empty when connected and you know its not empty then the float is probably bad.

[Kevinn]

I disconnected the tan wire and the fuel gauge doesnt move at all. I replaced the fuel gauge and going to see if it moves when I disconnect the tan wire. You could be right my light switch acts up sometimes doesnt work or cab light goes on without touching switch.

[randy500]

Why didn't you check for power and ground?
There is a fuse, cluster feed, upper right,
Does the temp gauge work? It powers that too.

[LockDoc]

Originally Posted by Kevinn

I have 1970 c10 396 bbc 1/2 ton and was trying to figure out why my dash lights dont work and my fuel gauge and I stumbled on this black wire with a blub not connected to anything and was wondering if need to be connected somewhere and if that's the cause why my gauge lights dont work. Also notice this grey wire with something on it dont know its for.I'll appreciate the feedback. P.s I'm new to this its my first car and learning bout this truck.

Your first picture is the fiber optic cable. The picture below shows where it installs in the back of the cluster. Insert it into the hole and turn it 1/4 turn to the right. Make sure it is seated all the way in the hole before you turn it.

The heater control bulb holder snaps into the hole in the back of the heater control assembly. (pic 2)

LockDoc

[rpmerf]

http://outintheshop.com/faq/wiring/w...s/image002.jpg

http://outintheshop.com/faq/wiring/w...s/image003.jpg

I would start out with a test light or multimeter and work your way from one end to the other. Make sure you have power and ground at the connector for the cluster. I don't know the terminals on the gauge, but you should be able to find that here somewhere.

Cluster lights circuit:
bulbs
printed circuit board on the back of the cluster
20 gauge Gray wire
fuse block
16 gauge Dark Green
Light switch

[Kevinn]

Originally Posted by randy500

Why didn't you check for power and ground?
There is a fuse, cluster feed, upper right,
Does the temp gauge work? It powers that too.

None of my gauges work except speedo and oil.

[phlegm]

Originally Posted by Kevinn

None of my gauges work except speedo and oil.

those two run off of other cables and not necessarily the circuit board dont they? Sound like the wiring harness or ckt board may be shot. But I dont have a gauge cluster, so not sure.