gauges are driving me nuts- gauge power ignition wires?

[plugugly]

SO i have spent hours trying to figure out why these damn gauges dont work. I have verified all gauges work individually, sourced a new resistor for the volt meter, check continutiy to grounds, etc, etc. Was expecting things to work today when I plugged it together and Nope, nada nothing.

So I checked continuity on the circuit pad itself. It seems to check out, so I start checking continuity for on the 3 pink/black wires that are ignition power to the circuit pad, and i seem to be getting resistance through them. There is power at the fuse panel(12 volts) but when it gets to the plug for the back of the gauge cluster, the 3 different ignition powers are all .12 volts. Im guessing this is why my voltmeter, oil press and water temp arent working?

this is the diagram I am working from

hoping someone konws what the hell is going on before I light this thing on fire.

 

[RustyPile]

Lets' get back to basics.. Checking continuity is all well and good, provided it's done properly.. Very first thing to check is fuses.. Make absolutely positive the gauge fuse is good, making good contact, and not blown.. Turn on the ignition switch and, using a test light or DVM, test for voltage on both sides of the fuse.. If voltage is not present on either side, check for voltage at and going through the ignition switch.. Repair as needed. If voltage is present on only one side of the fuse, that fuse is bad. (I'm guessing this is the problem). Replace as necessary.. If voltage is present on both sides, check for voltage on the instrument plug by back probing the plug on #6, #4, and #16 terminals.. If voltage is present on all three, you probably have broken trace on the circuit board. If voltage is absent on any one of the terminals, the wire leading to that terminal is broken or otherwise has an open somewhere along its length...

 

[plugugly]

there are no fuses on these pink/blk wires. Two go into one single fitting and the other is a single wire into the plug. They have 12 volts at the panel, and on the plug side of the wire. The same same wires at the gauge side plug goes down to .12 volts, so, and while I am certainly an electrical dummy, it seems to me that there is significant loss by the time it gets to the gauge panel. I dont know what else it can be. I am at a loss. I dont have a few of the bulbs attached to the panel, but those dont really seem to be terribly involved in the power/ground circuit.

the reason I mentioned the continuity is that it doesnt zero from plug to plug on the pink/black wires. it stays in the hundreds somewhere, so Im guessing there is an issue in the wiring? It also reads ohms between those same plugs.

 

[RustyPile]

All circuits have protection, either a fuse or fusible link.. In the case of the gauges, there is a fuse in the fuse box marked "gauge(s)".. As I explained in my post, start there.. If you have voltage on the terminal where it plugs into the instrument panel but no voltage on the circuit board side, check the connection between the circuit board "tab" and the plug's terminal. Since there is so little current flow, even a small amount of corrosion will cause loss of contact.. Polish those tabs with a pencil eraser. Those tabs are thin and flexible. They can easily move out of place or even break off.

 

[plugugly]

i do not have a gauges fuse, just the plugs i mentioned before, so maybe there is a fusible link?

here is what the voltmeter reads at the 18 pin location with key on engine off as well

 

[plugugly]

unless its the instr which may mean instruments, but that checks fine


EDIT: disregard, it apparently is intermittent. It is now not working. Im guessing that is my culprit. Ill have to pull the fuse panel and see whats going on with the back side of this thing.

 

[Matt69olds]

This is the gauge fuse.

 

[plugugly]

that was it! thank you so much. still not sure what the hell that fuse is labeled as, but that fixed my problem.

The other fuse is the cluster lighting for anyone who comes across this.

 

[Jgonick]

Just an FYI- These pink/blk wires are usually cruise control