Dash Suggestions and Questions

[Atchison0341]

Hi Gents,


So I will try and keep this short and sweet and to the point. I am working on a 1964 GMC short bed fleetside pick up. It has been in my family since it was new. My father passed the truck on to me after getting back from Iraq in 2007. It has been used as a DD since then. However shortly before that my uncle had it did a lot of rigging with it to get it working, he and my father no longer speak which makes it hard for me to figure a lot of things out. I know that I believe it has a 350 from a 1989 Chevy Suburban. Everything else to MY knowledge is original. I am only 28 and have done as much reading as I can.

Here is my current dilemma, the fuel gauge has never worked, always reads 1/4 full. So today I decided to try and fix it, I did my reading here following the steps as well as getting me a new OHM meter and checking my sending unit. The unit checked out fine. So I was curious about checking the gauge itself making sure its wires were connected correctly. ANd I came across what is pictured below.... I am no expert but to think that in 1964 they had all the wires together and run together at the back of the cluster seems off to me. So I'm here to ask, what year is this stuff from....and do you guys have any more advice on how I can fix my fuel gauge issue?












THANKS!!

[Heater63]

I don't see a pic attached.

[Atchison0341]

Originally Posted by Heater63

I don't see a pic attached.

The pics are showing up for me on my computer and IPhone? I think i did it correctly
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[Captainfab]

Welcome to the forum

I would start by cleaning all the metal connections on both the plug and the connection on the dash. Have you checked to see if you are getting power to the dash on the fuel gauge wire? Also check and clean the connections where the fuel gauge attaches on the back of the dash under those plastic caps.

[Atchison0341]

Originally Posted by Captainfab

Welcome to the forum

I would start by cleaning all the metal connections on both the plug and the connection on the dash. Have you checked to see if you are getting power to the dash on the fuel gauge wire? Also check and clean the connections where the fuel gauge attaches on the back of the dash under those plastic caps.

That was my next step cleaning them all. When you say under the plastic caps for the fuel gauge, every thing runs through that one connector that goes to the bottom, nothing plugs in the back of the fuel gauge.
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[Captainfab]

The 2 plastic caps to the left of the electrical plug should be covering the studs and nuts that attach the fuel gauge to the printed circuit. The printed circuit on the back of the instrument panel was a GMC only thing until '67.

Originally Posted by Atchison0341

That was my next step cleaning them all. When you say under the plastic caps for the fuel gauge, every thing runs through that one connector that goes to the bottom, nothing plugs in the back of the fuel gauge.
Posted via Mobile Device

[Atchison0341]

Originally Posted by Captainfab

Welcome to the forum

I would start by cleaning all the metal connections on both the plug and the connection on the dash. Have you checked to see if you are getting power to the dash on the fuel gauge wire? Also check and clean the connections where the fuel gauge attaches on the back of the dash under those plastic caps.

Thanks for the welcome, lots of knowledge. That was going to be my next step I was just trying to figure out if what I had was in fact the stock set up for a dash. I don't know why but I figured back in 1964 that they didn't wire everything together into one butt plug. I thought it was all wired individually if that makes any sense.

Also any advice on how to check the wires? I just picked up a multi meter yesterday and am learning the ropes.

[veltex]

In addition to cleaning and checking for voltage it might be helpful to make sure all connectors within the main plug fit tight, and also all grounds are good. The circuit board grounds can sometimes quit making a good connection. If the sender is good and it is the correct ohm range for the gage it is possible the gauge is bad. What ohm range is your tank sending unit (how many ohms when full)? That fuel gauge is for a 30ohm sender.
That is the correct cluster for 64-66 gmc.

[markeb01]

After you clean up all those sockets, I would apply some dielectric grease to them before snapping it all back together. That will insure a solid connection.

[corvettejim1968]

my fuel gauge is doing the same thing. shows 1/4 tank when it has power. just started doing this two weeks ago. 65 c10

[63burban]

Also check to make sure the float on the sending unit is empty, sometimes they take on gas and a new float is in order.

[ray_mcavoy]

Lots of good info & suggestions so far!

But if the connections, sending unit, float, etc. all check out okay and the fuel gauge still doesn't read over 1/4 with the tank full, take a look at the resistor on the back of the gauge.

The resistor should be a piece of fine strand wire wrapped around a rectangular insulator block that is secured to the back of the fuel gauge. You might have to take the cluster apart to see it. Anyway, if that resistor is damaged (fine wire broken) or simply isn't making good electrical contact with the fuel gauge terminals, it will prevent it from reading much over 1/4 tank even when everything else is okay.

[Atchison0341]

Wow guys thanks so much for the information!
I will begin with working on it more this weekend when I have time. I went ahead and ordered a new sending unit, only because Brother's had them 50% off.

[Heater63]

I can see now! Sorry about that Atchison, I was unable to see the pics on my pc the other day.
X2 all the info above. Also, make sure everything is grounded well...sending unit and the dash panel insert.

[Atchison0341]

Hey guys sorry been MIA last week and finally got a chance to take a look at things and I took the instrument cluster apart father and took the gauge itself out and this is what I found.... does this all look normal/ ok?

[BFoley]

Originally Posted by Atchison0341

Hey guys sorry been MIA last week and finally got a chance to take a look at things and I took the instrument cluster apart father and took the gauge itself out and this is what I found.... does this all look normal/ ok?

The coil connections seem solid and, visually-speaking, the coils don't look as though any "magic smoke" was let out. If the wire connection between the soldered connection and the coil is not broken, I would spend some time and do a continuity check or ohm check with a multimeter to verify a solid connection between the gauge cluster plug and the fuel tank unit connection. I believe this is a tan wire on both ends.

[Atchison0341]

Originally Posted by BFoley

The coil connections seem solid and, visually-speaking, the coils don't look as though any "magic smoke" was let out. If the wire connection between the soldered connection and the coil is not broken, I would spend some time and do a continuity check or ohm check with a multimeter to verify a solid connection between the gauge cluster plug and the fuel tank unit connection. I believe this is a tan wire on both ends.

Thanks for the reply thats the plans for this weekend. Just figured I'd ask and make sure the gauge itself was looking ok.

[oakstcustomz]

I always use a pencil eraser on the circuit board circuits to clean them up. One old timer also suggested ketchup as well although I've never tried. Just like cleaning a penny!

[Atchison0341]

Just run the eraser all over the circuit board? I'm willing to give anything a try

[64shortbed]

If you can't get it to work. i have an extra gauge cluster. I put all new after market gauges in my 64 gmc. All i'm keeping the cluster around for is the plastic. I'm not sure if its aloud but if you pay for shipping i'll send the gauges and and back side of plastic with the printed curcit board. Ill never use them. they worked when i took them out of my truck.

[Atchison0341]

Originally Posted by 64shortbed

If you can't get it to work. i have an extra gauge cluster. I put all new after market gauges in my 64 gmc. All i'm keeping the cluster around for is the plastic. I'm not sure if its aloud but if you pay for shipping i'll send the gauges and and back side of plastic with the printed curcit board. Ill never use them. they worked when i took them out of my truck.

I had actually looked at your dash before haha, it looks awesome. If I wasn't trying to keep the truck so original like my dad and grandfather did I would do something like yours.

Also it would be amazing if you'd let me buy the circut board and gauges from you. But just shipping isn't enough let me throw you some money for some beers or a bottle of whiskey? Just let me know

[64shortbed]

http://67-72chevytrucks.com/vboard/s...d.php?t=516023

[Atchison0341]

To update everyone:
Yesterday I was able to mess with it some more. I got a used gauge set. I installed my new sending unit, and hooked up the used set I just got, turn the ignition and get the needle bounce. Never started it because I've got the heater core out right now. Anyway I hooked up my cluster set click the ignition and got nothing. I tried this 3 more times to try and account for any error I may of made. Same results each time. So I decided to take my fuel gauge off my cluster and put it on the new used set. Then the ignition and my gauge does nothing, the temp gauge which I didn't mess with still did the initial jump. I'm assuming my gauges and circut board were bad? I for the life of me thanks to my PTSD meds can't recall if my gauges did this before I took them out. So I'm kind of stuck now.

[Captainfab]

Are you making sure the gauge cluster has a good ground?

[64shortbed]

The GMC dash cluster is all plastic so one of the wires going to it has to be the ground. I'd check to make sure all the connections are clean and that the ground it good. You should be able to take your sending unit out of the tank run a ground wire to it so its like its grounded to the tank and move the sending unit up and down and the gauge should move to show full to empty. The biggest thing is to make sure the sending unit matches the gauge as far as ohms. 60-65 0-30 ohms and 66 some where 0-90 ohms i think. That gauge i sent you are the 0-30 ohms

I found this and i hope it helps
http://67-72chevytrucks.com/vboard/s...d.php?t=352378