XJ6 & XJ12 Series I, II & III 1968-1992

Gauges in Instrument Panel Stopped Working

 
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Old 01-27-2019, 09:49 PM
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Default Gauges in Instrument Panel Stopped Working

All,

Starting the jag up today and none of the gauges in the instrument panel are working. I have read some older posts that were for later series xj's and all the issues were with bad fuses/fuse connections. I have looked at all the fuses and fuse diagram and all the connections and fuses look good, plus none of the fuses seem to connect with the instrument cluster. The instrument reference for fuse one looks like its just the tachometer and speedometer. I havent noticed anything else electrically that is not working.

Is there anything else I can be testing to figure out if its a bad connection somewhere else? Any ideas on next thing to check?

On a good note at this point Im keeping the car. I was thinking about selling it since I wont be able to finish the cosmetics anytime soon, but it can look like a rat rod for awhile. Also with not putting any more major funds in the car at this point, Im going to have to get my hands dirty more and fix whatever breaks.


 
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Old 01-27-2019, 10:45 PM
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What year and model is your car? Mine is an 87 XJ6 and fuse number 4 is the one for the gauges. Get a digital multimeter (I got mine at Lowe's for $20) and read the voltage on both ends of each fuse. They should all be at least 13 volts with the engine running.

Jeff
 
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Old 01-28-2019, 04:56 AM
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fuses have a nasty habit of looking fine even when they are not. Replace the fuse in question and try again.
 
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Old 01-28-2019, 06:48 AM
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I have a 73' xj12. So I have 13V across fuse #4 and also #1-3, however starting at fuse 5-10 i am not measuring any voltage across it. #5-10 are related to lighting and all my lighting seems to be operating normally so not sure what that means.

Based on the chart in my first photo I do not see any fuses that seem to indicate they would control the instrument panel, so not sure which one i should be checking. Is there any place I should measure voltage at the panel to see if its getting power?

Thanks for your input! Im sorry for my negligence, trying to learn how all this is working
 
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Old 01-28-2019, 07:28 AM
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we all run into these kinds of mysteries, no need to apologize. Assumedly you are checking voltage with engine running or ignition switch ON??

is the screen washer and horn working? they are protected by Fuse #1 as the Revolutions Counter (Tach) and the other instruments.
 
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Old 01-28-2019, 07:37 AM
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Yes engine was on. The horn was working along with the Tach and Speedometer, but screen washer has never worked for me. That will be something to look at later

Its just those 4 center gauges not working...
 
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Old 01-28-2019, 07:47 AM
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then it has to be Fuse No. 1
 
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Old 01-28-2019, 09:58 AM
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Jose means it should be that fuse. If it broke in the past and someone just rewired to another 12+ circuit your just going to trace back until you identify where the power is actually coming from. Or you can do that and get a good known 12+ and wire it to the guages yourself. Easy for you, hard for some guy 25 years from now trying to fix it again .
 
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Old 01-28-2019, 10:30 AM
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my comment is under the assumption that the wiring is unmolested. It if has been rewired, that's another $20. per hour.
 
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Old 01-28-2019, 11:28 AM
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So on my quick lunch break at the house I popped out fuse #1 and the tach. stopped working and popped in a new fuse and the tach came back on but none of the 4 other gauges appear to be working still.

I found this 7 wire plug going into the gauge cluster and all appears normal. I measured 13V at wire 7 just like the wire diagram shown below....

Not super familiar with wiring diagrams though. Do i need to trace that 7 wire cluster back? I am going to be getting a bunch of fuses just to replace them all but at this point, not sure if thats the problem.


 
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Old 01-28-2019, 12:28 PM
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Assuming an electrical device is operational, it needs 2 things to work, 12+ and a good ground wire. If you have power, check the ground. Replacing all fuses is always a good idea. I often use little jumper wires for trouble shooting. You can clip a wire with a known good 12+ and another one to a good ground to see if the darned things work. They also make it easier to use a multimeter.
 
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Old 01-28-2019, 01:03 PM
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Here is a photo of my essential electrical tools. Test light (I call it the ice pick), note the little piece of rubber tubing that goes on the really sharp tip so I don't stab myself. $20 multimeter. Assortment of jumper wires. Another tip is to get an uninsulated ring terminal and put it under one of the screws on the metal housing of the fuse holder. Then you always have a good ground for the test light so the little alligator clip doesn't keep slipping off.

 
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Old 01-28-2019, 01:23 PM
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you can get decent digital multimeters for free at Harbor Freight Tools, there is always a number of FREE things you can get when you buy something no matter the price. They last as long as they do, and if it dies, it was free.

I have three already and they're still ticking.
 

Last edited by Jose; 01-29-2019 at 05:14 AM.
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Old 01-28-2019, 01:35 PM
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i got a good multi-meter but those jumpers will come in handy, ill pick them up! the next to check seems to be the ground, which ill do tonight.

If its not the ground then i can try and jump the power, as mentioned above by Yellow3. Now with this 7 wire cluster that slides up against the "blueish" circuit board where would i bring the power to? if i touched the jumper up against where the #7 wire would make contact based on the diagram above would it be fair to say the left two gauges should work (#146 & #43)

thanks so much for your help, i need to get some confidence in working on this car, and this is the first test i gotta pass. Hard driving with not seeing the gas gauge and oil pressure
 
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Old 01-28-2019, 01:46 PM
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Been looking at your wiring diagram. The guage on the left is evidently the volt meter. That is the simplest as it has 12+ going in and the other terminal grounded (probably real close to the guage). The other gauges like temp and oil are grounded at the sensors on the engine. So if you use jumpers and determine the volt guage is working then it is easy to check the original wires for power and ground. So you should be able to quickly get the volt guage working and can then work on the others. If they all stopped working at once I would highly suspect the ground connection.
 
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Old 01-28-2019, 01:54 PM
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in the series 3, there are gauge-to-gauge ground wires which end at a spade terminal junction on either side of the tach or speedo which is bolted to the steel frame behind the wood dash.

I would look behind the dash to make sure the ground connector has not separated at the junction, assuming it is the same wiring as the Series 3.
 
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Old 01-28-2019, 07:54 PM
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I havent had a chance to get the extra fuses or jumpers but i did check what looked to be the grounds coming off the gauge cluster, a couple black cables. I tried taking photos, sorry if not the best quality. The red circles are what looks to be the ground? Connections looked ok, not sure how to "test" it.

I figured out how to take the dash cap off easy enough, but to get behind the dash do i just remove the couple screws on the left side once you fold the instrument panel down? Ill check there next like Jose mentioned. Thanks all!

 
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Old 01-29-2019, 05:24 AM
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with the center fold-out panel it is a Series 1, closer to the 420, MK-2, MK-X, and S type.

I would leave the wood dash and center panel alone, not remove them. Removing the wood will not fix it.

you either have a Ground wire that came loose, or a blown fuse. Second to that but a rare ocurrence, would be the Gauges Voltage Regulator usually mounted to the firewall behind the center fold-out panel. At least there is one in the previous cars I mentioned, I am not familiar with the Series 1 but it just cannot be THAT different.
 
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Old 01-29-2019, 12:05 PM
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Not sure if your question was how to test a circuit ground or not. If so, use your jumper wires to go from a good solid known ground to the grounding point on the device. Be sure to scratch around until you see bright shiny metal to get a good connection. If it works with the jumper and not without it, you know the factory ground is bad. Those spade terminals in the photos are the easiest to clean and maintain. The absolute best ground on the car is the negative post of the battery.

I don't know if they actually sell jumper wires but they do sell little packets of the alligator clips so it is easy to make your own set. Be sure to color code them. Sometimes you get a jumble of wires and it is important to be able to easily tell which one is which.
 
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Old 01-31-2019, 07:06 AM
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So still been stumped on this problem but upon further investigation of the instrument panel circuit, not the power and ground connections, there is a break in the circuit right behind the clock. I couldnt see it originally because the clock blocks it.

Assuming this is the problem for all the gauges is there a way to repair this or no i need to replace the instrument panel?

See the picture for reference.
 

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