I'm desperate gauge cluster help

[Doorjam13]

I have posted something about this a while back and did the things that were recommended and still I can't get any of the cluster to work.

So for the only thing that works is the mechanical speedo and the blinker, None of the backlights or the other gages work. I have power to circuit board and light bulbs are new. I also checked the ground wires. I have cleaned all the electric contacts.

I'm at a loss I don't know what to do next.

[basketcase0302]

"Doorjam13"] I have posted something about this a while back and did the things that were recommended and still I can't get any of the cluster to work.
So for the only thing that works is the mechanical speedo and the blinker, None of the backlights or the other gages work. I have power to circuit board and light bulbs are new. I also checked the ground wires. I have cleaned all the electric contacts.
I'm at a loss I don't know what to do next.

Do you mean just the lights for the panel don't work? It gets it's power from the rheostat on the headlight switch which is a common failure causing loss of power to the panel.
You said you have power to the panel-exactly what voltage are you reading there and what year truck is this?

[Doorjam13]

I don't have a voltage meter.... as of yet. All other lights work on the truck except the cluster lights(light the back of the gauges to see at night) The blinker indicator in the cluster does works. And the guages themselves do not read anything(oil, fuel, temp and volts).

[basketcase0302]

"Doorjam13"]I don't have a voltage meter.... as of yet. All other lights work on the truck except the cluster lights(light the back of the gauges to see at night) The blinker indicator in the cluster does works. And the guages themselves do not read anything(oil, fuel, temp and volts).

What year truck is this, (will help for future issues if you put a year model truck in your signature as each are different) helps us-to help you.
Earlier models of the bump trucks had hard wiring on the back of the instrument panel and the later models had a printed circuit board for the lighting and gauge wiring on the instrument panel-so we first need to know what year truck it is.

[Doorjam13]

1972

[basketcase0302]

"Doorjam13"]1972

Your 1972 will have the printed circuit board on the back like part number 10K843 in the top image on this page, (unless someone has changed out the panel which is doubtful):


Here's another good image of what your looking at. The harness plugs into the printed circuit board and powers the lamps, (part number 13711 of which there are six of them). A lot of times these bulbs are the issue and are also easily tested (also using a voltage meter-a crummy "test probe" will also be useless to test the bulbs):


You really first need to get a cheap voltage meter which can be bought anywhere for less than $10.00 like this one-and easily learn to read it here on the forum, (not a crummy test lamp that destroys your wiring harness by piercing the wiring insulation) and test for "voltage" (not just "power) to the instrument panel (as once again it gets "voltage" from the headlight switch rheostat) and you need to know exactly what it is getting :
https://www.harborfreight.com/7-functio ... 90899.html

Once you've determined the voltage from the headlight switch rheostat is correct, (should be anywhere from 5 VDC to 12 VDC) then you start testing the "sockets" on your instrument panel circuit board. You need to test for voltage on wire #19 A/B in this image (which is the blue with red stripe wire in the harness that feeds the instrument panel).

[Doorjam13]

I have zero volts at the Blue w/red wire but 11.4 ish from the other wires at the head light switch.

[basketcase0302]

"Doorjam13"]I have zero volts at the Blue w/red wire but 11.4 ish from the other wires at the head light switch.

If you are measuring zero volts on the blue with red stripe wire (measuring at the wire end on the instrument panel harness-with the harness unplugged from the panel) your headlight switch is bad as earlier suggested.
The rheostat that supplies power to that wire, (from the headlight switch) gets it's power off of a spring (you'll see it when you pull out the headlight switch-it lies behind the round white ceramic piece in the below link photo) and a bimetallic strip that has a contact point on it that wears out frequently.
The good thing is the headlight switch is a cheap enough and readily available part (real easy to find) but order a good one or you'll be very disappointed as some of the quality of the new ones are as bad as the old FoMoCo part you'd be pulling out.

DC has it and I'd def pay the extra $10-you'll be so...glad you did with this part:
http://dennis-carpenter.com/headlight-s ... Z-11654-A/

[Doorjam13]

So I put in the new headlight switch and I now have lights in the dash

My fuel and ALT gauge is still not functioning. I have an auxiliary water temp and oil pressure gauge I'm not sure if the original ones are working.

[basketcase0302]

"Doorjam13"]So I put in the new headlight switch and I now have lights in the dash
My fuel and ALT gauge is still not functioning. I have an auxiliary water temp and oil pressure gauge I'm not sure if the original ones are working.

These are all separate issues that have to be dealt with one at a time. Good deal on the dash / instrument panel lights as the printed circuit board is a pricey item if that were the culprit.

The fuel gauge would be the next thing I'd tackle. Take the volt meter, (test light will be of no use whatsoever for this also) and test for power at the fuel sending unit supply voltage wire behind the seat on the tank sending unit. The gas tank sending unit, (behind the seat in the top of the tank) will likely be the fault there as the gauge itself rarely fails.

[Doorjam13]

Tested the ohms on the sending unit and I got about 80 to 90 ohms. The tank is almost full.

[basketcase0302]

"Doorjam13"]Tested the ohms on the sending unit and I got about 80 to 90 ohms. The tank is almost full.

Are you sure you zeroed your meter before you took that reading?
From the tutorial you should read the following:
"Verify by hooking up an ohmmeter to it and making sure it reads 8-12 ohms full and 70-73 ohms empty."
But I would first start with checking for 5 volts as earlier suggested.
You can also easily pull the sending unit once you've verified you have voltage by removing the six screws that hole if in. More often than not you'll find the float, (usually brass) has a pin hole in it and is full of gas making the gauge either not work or just not be accurate. The float and sending unit can both be purchased from a few different vendors I'd recommend DC as they have good parts:
http://dennis-carpenter.com/?source=adw ... oCdMzw_wcB

And here's the fuel tank sending unit tutorial on how to troubleshoot it:

http://www.fordification.com/tech/fuel- ... -units.htm