Electric issue...

[Fleurya]

So my fuel, oil pressure and voltage gauge were not working and would not make anything even when putting the switch on run or start... also the wait light wasnt working but only flickering... installed new grounding harness, smart box and HSU and now wait light is fixed but still having issues with gauges...
volt goes all the way to the right, oil pressure and fuel not functioning at all...
also changed glow plugs.
Also have issues with turn signals and stop lights...
Any input?
Where in the TM can I find the electric diagrams?
Appreciate your wisdom!!



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[DamageControlCustoms]

Hello,

Did you undo the cluster? When you open up the cluster, to the right, behind the heat control, you should have two wires hooking up to your ground.

 

[dmetalmiki]

As mentioned, the grounds are crucial on the dash.

 

[Action]

The ground connection behind the heater controls has wires on both sides of the firewall. Clean those wire ends and replace the rusty bolt.

 

[papakb]

Because of the way the body is constructed on the HMMWV I chose to put a 1/4-20 stainless steel stud thru the firewall behind the heater controls with star washers and nuts on both sides. All of it was coated with De-Oxit electrical antioxidizing grease to prevent future issues with body bonding (grounding). I now use Dow Corning DC4 grease which is more expensive but it prevents oxidation, softens hardened rubber connectors, and makes them slip together and apart easily. The supplemental ground harness connects inside the engine compartment and the gauge panel and master light switch ground lead connect inside the body.

BTW, the electrical schematics are in TM 9-2320-280-20-3 all the way at the end of the manual. They're large foldouts so you have to enlarge them and then look at one section at a time.

When I first got my vehicle I took the schematic that matched my truck down to the local copy shop and had it copied double size and then laminated. That way I could hang it on the wall and follow lines with a grease pencil (china marker) to trace the circuits and then clean it all off to use again.

 

[Fleurya]

The ground connection behind the heater controls has wires on both sides of the firewall. Clean those wire ends and replace the rusty bolt.

Would you be able to take a pic of the wire and bolt that you are talking about? I dont see it... maybe I am not looking at the right place or it is not there and that is the issue...


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[Action]

No i cant.
Remove the 4 screws holding the gauge cluster in. Pull the cluster out. You may need to unscrew speedo cable. The bolt will be in there to the upper right side pointing towards the front. Right behind the push/ pull heater knobs.