Clusters, Gauges, Speedo & Odo meters (1 Viewer)

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Yes, I have a meter, so we can do some testing. Is this to determine if my fuel gage has other problems ?

And my face plate of the gage is still attached, so I will be attempting this repair w/o removing it.

Thanks, John

Yes, I like to do some tests before you put the whole thing back to find out that it still doesn't work.
Better do it right the first time. Right? Right!

Rudi
 
Agreed.

Ok, going to my workbench w/meter, gage & computer.

John
 
Here we go:
Left stud to right stud: this is the gauge; 25 ohm
[STRIKE]Top[/STRIKE] Right stud to bottom folded lip: this is the VR; 113 ohm
Top stud to right stud: this is the power for the TEMP gauge 0 ohm. This is also the "switch" from the VR and should be in the "closed" position. If the reading is infinity or open loop it means that the contacts are dirty. You have to clean/polish them.
I do that with a tiny piece of sanding paper 500 or higher. Open the contact with a toothpick, place sanding paper in between and slide this up and down a few times.

Good luck,

Rudi

There was a error inline 3.
 
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Here we go:
Left stud to right stud: this is the gauge; 25 ohm
Top stud to bottom folded lip: this is the VR; 113 ohm
Top stud to right stud: this is the power for the TEMP gauge 0 ohm. This is also the "switch" from the VR and should be in the "closed" position. If the reading is infinity or open loop it means that the contacts are dirty. You have to clean/polish them.
I do that with a tiny piece of sanding paper 500 or higher. Open the contact with a toothpick, place sanding paper in between and slide this up and down a few times.

Good luck,

Rudi

I am using a digital meter & testing from the rear of the gage. So this is how I read what you are calling right & left.

Right=the side of gage that reads Empty.
Left=the side of gage that reads Full.

1) L stud to R stud : my meter did not move.
2) Top stud to 'bottom folded lip' : my meter did not move. ie not zero...did not move/change. Not sure what you mean by bottom folded lip. I went to what I believe is the ground.
3) Top stud to R stud : my meter was 26.8.

So, I think I may not be testing what you are wanting me to test...sorry. Any way to be more precise to this electrical novice ?? Sorry.

Thanks for your help. Pls let me know what I need to do, or if you think my gage is toast.

Thanks, John
 
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OK, my previous posting was for looking at the face plate.

DSC00191a.JPG

This one is for looking at the back as in the pic.
Top to left: 0 ohm (short) that's the broken wire you have to fix.
Left to right: 25 ohm
Top to right: 25 ohm
Left to bottom folded lip (ground): 113 ohm
Right to bottom folded lip: 138 ohm

Rudi
 
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1) L stud to R stud : my meter did not move. Problably dirty contact.
2) Top stud to 'bottom folded lip' : my meter did not move. ie not zero...did not move/change. Not sure what you mean by bottom folded lip. I went to what I believe is the ground. You have to fix that broken wire first.
3) Top stud to R stud : my meter was 26.8. This is OK!


Thanks, John

My text in red

Rudi
 
OK, my previous posting was for looking at the face plate.

View attachment 591663
This one is for looking at the back as in the pic.
Top to left: 0 ohm (short) that's the broken wire you have to fix.
Left to right: 25 ohm
Top to right: 25 ohm
Left to bottom folded lip (ground): 113 ohm
Right to bottom folded lip: 138 ohm

Rudi

Thanks Rudi, w/your orientation, my readings are :
A) Top to Left : No reading until I fix wire.
B) Left to Right : My meter does not move.
C) Top to Right : Reads 25.9
D) Left to Ground :My meter dies not move.
E) Right to Ground : My meter does not move.

Whatcha think ??
Thanks, John
 
Thanks Rudi, w/your orientation, my readings are :
A) Top to Left : No reading until I fix wire.
B) Left to Right : My meter does not move. Contact problem
C) Top to Right : Reads 25.9 √ OK
D) Left to Ground :My meter dies not move. The same contact problem
E) Right to Ground : My meter does not move. The same contact problem

Whatcha think ??
Thanks, John

My text in red

See pic below, I think tyou have to clean the contact points first and have a good look in that area to see if there is any other problem.
DSC00296b.JPG


I'll see if I can make another diagram to show what and why the trouble maker is.

Rudi
 
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Thanks Rudi,

Will clean & retest tomorrow. To complete this meter testing do I need to repair the wire 1st ??

B/4 retesting I will cleanup those contact points. I will do a beter job of cleaning, but I did clean them up a few days ago when I started this process.

Thanks for your time man, really appreciate it. Will get back tomorrow.

John
 
Yes, you have to fix that wire and make sure that contact is in good condition.

I made a diagram so you can see how it works compared to the unit on your bench.
Note that the blue triangle represents the "dirty contact" so all measurements from that stud will fail if that contact is bad.
fuel and vr drawing.JPG

OK, tomorrow is another day. Time for a :beer: or 2?

Rudi
 
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Hi Rudi,

W/much help from a friend via the phone & your outstanding post, I have made progress but still have some issues that you may be able offer thoughts on.

Here is my update :

1) Now have the fuel gage working but not the temp gage.
2) Fuel gage needle is now more sensitive to RPM's. Will move ever so slightly w/rpm's. Not much & I can live w/this but seems to indicate fault w/VR.
3) Fuel & oil pressure are sensitive to my movement of the wires at back of the harness that plugs into the circut board. Moving the bundle of wires will ALWAYS get fuel/oil to work.

Think I can work through #'s 2 & 3. No. 1 is where I need your help. Here is what I have done so far:

A) Twisted 3 strands of elec wire together & soldered it from middle post over to VR.
B) Cleaned up the ground tab under the fuel gage.
C) Now able to get the values you suggested in post 45
D) Tightened up the female connections in the harness/plug that goes to the circut board. Now nice & tight.
E) The temp gage wire (YG) in the harness that plugs into the cluster ohms at 89 after running engine for 5 min. Thinking this indicates the temp sending unit on the block is working.

SPECIAL NOTE: This may/may not be important. Without knowing it I manhandled the gages while shinning things up. Oil needle was bent at 90*. Gently bent it back & all seems well. Don't think I manhandled the temp gage but it does not sit at rest where it did before. At rest it used to sit at 'C' & was visiable in the gage cluster once in truck. Now, it's there but you have to look for it. After running engine 5 mins. it does not move. Getting ready to remove temp gage & take a look.

Ok, that's it. What do you suggest as my next move to determine why the temp is DOA.

Thank you much.

John
 
I 'think' I have found/fixed the problem that I described in post 51. I believe all is well, with all gages working but won't be certain until I put it all back together & hook up the cluster tomorrow.

Here is my diagnosis : I manhandled the temp needle more than I thought. To the naked eye there was no visable damage. In reality, I had unknowingly pressed the keeper (little white plastic donut shaped item that holds the temp needle to the gage) too tight aganist the needle, which did not allow the needle to move...even tho it was getting the proper signal. This keeper is VERY small, a sewing needle will go into the donut hole...but not very far.

That's my theory, will test it tomorrow & get back to you. I can move the needle freely now, where before it was stiff & would not move.

Greatly appreciate your time...talk tomorrow.

John
 
OK, good job! So the Fuel gauge is working now. :bounce::bounce2:
You'll see a very tiny movement of the needle when you rev the engine. This is because at idle there is 12V and at higher rpm's the voltage is 14 or 14.4V and that will influence the working of all gauges. Don't worry about that. While I'm typing this and looking back at your post I see that you probably solved the TEMP gauge problem. :clap:
I keep my fingers crossed for tomorrow!

Let's talk tomorrow

Happy driving :steer:

Rudi
 
OK, good job! So the Fuel gauge is working now. :bounce::bounce2:
You'll see a very tiny movement of the needle when you rev the engine. This is because at idle there is 12V and at higher rpm's the voltage is 14 or 14.4V and that will influence the working of all gauges. Don't worry about that. While I'm typing this and looking back at your post I see that you probably solved the TEMP gauge problem. :clap:
I keep my fingers crossed for tomorrow!

Let's talk tomorrow

Happy driving :steer:

Rudi

Thank you Rudi, Your help has been invaluable. I knew I was never far from expert help.

Yes, we will talk tomorrow. Not counting my chickens just yet but I think we may have done it. Will hook it all up & let you know.

Thanks,
John
 
This kind of encyclopedia of clusters and gauges. Very nice.
 
Thank you for your help Rudi, I think it's fixed. Most certainly w/o you expert help I would still be stumped. Hopefully others can learn from this thread.

Hooked everthing up and at least in the driveway all seems to be A-OK. All gages seem to be sitting at correct values.

Between you & my friend we spent several days testing, checking, hooking things back up & then more testing. In the end the culprit was the unseen broken wire from the top middle post over to the VR.

The reason I did not see the broken wire is because for several days I attempted to do the testing/repair w/fuel gage still attached to the cluster. I was unable to detect the broken wire because of other items blocking my view of the insides of the actual fuel gage. For others having a non-working fuel gage, I would suggest actually removing the gage for a better look see. My 1 hr. fix ended up causing a lot of drama & 3 days of 'fixing'.

My concern now is why did this wire blow in the 1st place. And did that wire act as a fuseable link, and if so, do I have a potential fire hazzard w/my repair of twisting 3 automotive electrical wires together & soldering it in place of the 'FL'.

Or am I just overthinking this ? Would appreciate your thoughts.

And I can not begin to express my (and I am sure the rest of MUD) apprectation to you for putting this thread together. One of the most detailed I have seen.

Thank you,
John
 
Hi John, glad all gauges are working now.
Why that wire broke?....... no idea. If it was burned it should be blueish / black looking but I understand that's not the case.
That wire is just the connection between the VR and both gauges so there is no reason for burning because the VR would respond much faster to an overload.
Anyway, in electronics we have to accept that parts are malfunctioning and we will never know the reason why or what was causing it.

Happy driving! :steer:

Rudi
 
Ok good to know.

Just getting ready to use the search function...but since you are on now, I will ask you.

What if any lube do you suggest on the odometer gears in the cluster b/4 putting everything back ?

By the way I am also putting on a new speedo cable. A non OEM cable snapped last week. I don't believe it was from lack of lube, but I can get to it so....

Thanks,
John
 
BJ40 Body Electrical FSM


Hello Rudi, thank you very much for sharing all this information. I have a long time looking for a post like this[FONT=&quot] (with details, pictures, etc)
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I am looking for the complete FSM of electrical body (the one you used to explain how to fix the cluster gauges) I cant find it anywere and need info about the hazard switch, back up switch, etc… and maybe you have or know where this can be found. My TLC its a BJ40 ´75 with 24V electrical system.
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