How to wire fuel gauge and sending unit complete explanation

In this video I show, you how to connect the wires on a fuel gauge without a multimeter using a battery. I also show you how to test and diagnose the gauge using only a car battery.

[@rickwaters7459]

love your comment about plastic 😂😂and totally agree, gauge number 2 is far better.. thank you for a simple explanation how fuel gauges work and the potential problems..

[@OldCrowsClassicCars]

Thanks for taking the time to show your support. Very few people do!

[@rickwaters7459]

@@OldCrowsClassicCars thank you again.

[@OldCrowsClassicCars]

@@rickwaters7459 My pleasure

[@lovelysharma0741]

😂😅y😮.lp​@@OldCrowsClassicCars

[@ramdeosingh8262]

❤❤❤😊😅​@@OldCrowsClassicCars

[@Keystone2066]

Your advice on having to ground the sender was spot on. The instructions do not tell us that!!! I installed the unit in a plastic fuel tank and it did not work. I ran a ground wire from one of the five screws on the sender to the truck body and now it works = all good. Thanks!!!

[@OldCrowsClassicCars]

Glad it helped!

[@SJGPerspective]

Great easy to understand video, I watched so many other videos, and no one else demonstrated as clearly and quickly as you did. Thanks man.

[@OldCrowsClassicCars]

That was the intention! Glad it helped!

[@belkwaydesigns3146]

😊😊

[@PatHaskell]

About to go and troubleshoot my fuel gauge and found your video…very helpful. Love the unedited quality😃, entertaining!

[@OldCrowsClassicCars]

Glad it was helpfull to you! And yes, even I look back and think it was entertaining. haha

[@thecraftycorner4002]

Thank you for this video. I've been searching for this simple full explanation.

[@OldCrowsClassicCars]

Thank you so much

[@edpewter4512]

Thank you. Easy to understand.

[@edpewter4512]

God says that what goes into a man is not what defiles him but that which comes out of a man is what defiles him.

[@victoremberda]

Thanks brother, I got some idea on how to install fuel guage connection. God bless you bro. From Vic Emberda a proud filipino.

[@OldCrowsClassicCars]

I'm glad it helped. Be sure to share the video with anyone else that may need it. I also have a few other videos on how to repair a common problem with these gauges if you need. Cheers

[@diceman220]

Awesome, you made it to easy. Thanks

[@OldCrowsClassicCars]

Thanks so much! I'm glad someone was able to use this info!

[@victormartinez6936]

thank you sir. this video definitely cleared up things for me. I got a gauge that register full when ignition ON and register half full when ignition off

[@OldCrowsClassicCars]

Glad to hear !

[@allaboutgames531]

So is mine guess I need to check the ground wire

[@JohnSmith-ub5vn]

Thank you for this video, may God bless you.

[@OldCrowsClassicCars]

Thank you! Merry Christmas.

[@harrywalker5836]

@@OldCrowsClassicCars hi,i bought chineseium gauges. 2 off, non work. just bought indian 5 gauge set, smiths nok offs. . $45, for full set,but the tach is cable driven. you hate plastic,i hate chinese products. with the cheap labour,they should be best in the world, better than japan. good tools are teiwanese. they take pride..

[@frankdavidson9675]

you need run a wire from the base of the sender to the ground post on gauge also run a wire from base to neg post on battery what you are doing now is adding rthe resitance of the batt,in series with the sender total res. from sender has to be 33 to 240 ohms

[@joseantoniodorosario729]

Thank you Sir. Very useful for me. 👍

[@OldCrowsClassicCars]

I'm glad I could help!

[@ThomasPrior-wv6zn]

yes i also lik you had to find out about the grounding my sender all ways showed full some times its best to find it out yourself good luck

[@mirtaviettro1823]

Very good explanation men! best on youtube!

[@OldCrowsClassicCars]

0:18 I meant the fuel gauge AND the sender AND shipping cost $20...probably around $80 at the average autoshop.

[@frankdavidson9675]

you need to wire the batt with 2 wires to gauge also wire sender wi 2 wires to gauge that will conn. the sender wire to the batt neg on the gauge that will make the test setup your useing work needle will follow the sender up and down if both are ok and 12 volts items some gauges are 24volt s

[@kevinholgerson5767]

Thank you

[@OldCrowsClassicCars]

You're welcome

[@brandonbaker8584]

Wow bud. I was with you for a min. My child and I are working on an 87 squarebody. But had to cut you off due to language. You tube should put age restriction on this one haha. Take care

[@OldCrowsClassicCars]

I Hope the video helped you. Yes, I was very stressed out during the time I did this video. Most of my videos now don't have so much colourful language. I usually put my videos as not suitable for children. Anyways in life you have to learn to filter out good things and bad things so maybe a lesson can be drawn from it lol. Besides, most of the kids I knew used to have alot of language and they turned out to be fine people. Good luck with your project and let me know if you need any help. Cheers

[@noeu8414]

Best video

[@OldCrowsClassicCars]

Oh ya!

[@JasonVoorhees-je9xc]

Excellent

[@OldCrowsClassicCars]

Thank you! Cheers!

[@williambrown238]

Amazon has all sort of sending units for sale with or without gage. They have both impedance types.

[@OldCrowsClassicCars]

Interesting. I switched away from these electrical gauges and went back to old fashioned dip stick. Mechanical gauges (used in airplanes) would be awesome too.

[@fermanloser3175]

Good tutorial but for future videos, you might want to invest in some jumper leads with alligator clips to free up your hands.

[@OldCrowsClassicCars]

I have them but most people don't. I also wanted to keep things as simple as possible

[@deankay4434]

@Ferman Loser >Yes, make a set of jumper leads for testing, use 18 AWG will carry 20 amps safely over 14 feet. I use an inline ATC/ATO fuse holder 12” from one end. A large clip battery size and smaller one, but soldered & shrink tubing used. I have a test lead for ground tests, but 20’, 16’, 12’ and a couple 7 foot long. Oxygen free copper, pre-tinned and PTFE insulation increase testing length. Most people don’t have them is right, but they don’t own a digital multi meter (DMM). Silicone rubber is common on meters with factory leads. Over 20 foot is sometimes needed on large boats and 1972 Chrysler New Yorkers for low resistance testing. ASE Master Tech since 1978 - Retired

[@rafaelvillareal9778]

Mannn, I am with you brother. I hate plastic too. Good video, and stay positive!!

[@OldCrowsClassicCars]

Those early days I was under alot of issues and stress.

[@joedymott6286]

Hi I'm 3 years late watching your video on fuel cage feel the same a classic car gauge should look classic not, plastic. You can sometimes swap the insides out of your old gauge put it in the new one hope this is some help for the future.

[@OldCrowsClassicCars]

Yes, you are right. I personally though would like to get some mechanical gauges, such as the ones used on boats and small aircraft.

[@DaySleeper-ml8ds]

I've got a question for you. How does a person find out what ohms the sender is and what ohms the gauge is, to make them useful together? I bought a gauge years ago and nothing is printed on the package about ohms at all. I also ordered a sender from a different company and same thing ---- nothing mentioned about ohms. Not knowing anything about ohms and such the sender was mounted in a tank under a truck and now I have a problem. Something is not working correctly and the wiring is correct. The gauge jumps to full but only two gals in tank. I will make this work but I don't want someone else to have this same problem. What do you think?

[@OldCrowsClassicCars]

Good point. You need an ohmeter. It should be part of most multimeteres . Measuring resistance on the sending unit isn't hard. A bit trickier on the gauge itself. I'd have to open one up, figure out how it works in order to provide a decent explanation.

[@frankdavidson9675]

the info im telling you is for the bench test only remember on the car the gauge is already grouned but you should have two wires coming from the sender one conn. to s the other to gd, on the bench you have to conn. batt and sender to make it on the bench

[@OldCrowsClassicCars]

Yes, I do that later on. I just didn't do it in the beginning to show the symptoms, what would happen if you didn't connect a certain wire.

[@mollymcelroy6814]

"trying to be the camera man here (oh for fuck sakes")

[@OldCrowsClassicCars]

;D

[@michaelorosco4958]

I grounded mine to the frame. Do I need a wire from my sending unit to the negative? Or from the gauge itself to the negative

[@OldCrowsClassicCars]

Short answer is YES. The entire car should be a negative terminal (ground). Does that answer your question?

[@koldenrjk]

YIKES

[@nathanrixmann7348]

So say if you have a sending unit that operates at for example "22 ohms empty to 140 ohms full" and the gauge operates at "140 ohms empty to 22 ohms full" can you swap the negative and positive on the gauge to swap its needle position? Just like a potentiometer?

[@OldCrowsClassicCars]

A potentiometer or variable resistor is exactly what it is. The resistances of the sender and gauge have to match. I'm not sure of exact numbers and unfortunately, not all sellers list these, so usually it's just best to buy both together. I however, have moved away from these electrical gauges and moved to mechanical gauges (which are used in airplanes).

[@nathanrixmann7348]

@@OldCrowsClassicCars I didn't know know airplanes used mechanical sending units, thats an interesting direction

[@OldCrowsClassicCars]

@@nathanrixmann7348 Yes, small airplanes (2 or 4 seats). They used them because their indestructible, whereas the electrical ones, theres alot of things that can and eventually do go wrong (corroded and loose wires, water/rust in gauge, worn potentiometer, wrong resistance , worn rubber insulator (check my video) etc). As you can see, these gauges are extremely week and sensitive. The one on the video actually broke inside the tank eventually. But a mechanical gauge, it's just gears...hard to damage those. The other type is an extremely simple dipstick...standard in cars from the 20s and 30s I believe.

[@carleonesLima]

Olá Tom ! Boa noite, vim do canal, garagem ca

[@OldCrowsClassicCars]

Opa, muito obrigado. Espero que goste dos videos. Maioria em ingles, mas tem varios em portugues tambem.

[@frankdavidson9675]

you can veryfi the sender with a ohm meter connect merter leads to cener post and other lead the round base on the right on your meter it should read full 33 ohms empty 240 + or - 10 ohms if so the sender is ok this is usa version forien types will read o to 100 i hope it helps somebody

[@frankdavidson9675]

also you can not use american sender and forien gauge will not work

[@OldCrowsClassicCars]

Thats right

[@carleonesLima]

Sou daqui de Camacan, Bahia Brasil.

[@OldCrowsClassicCars]

oxente, Aquele abraco!

[@carleonesLima]

@@OldCrowsClassicCars kkkkkk

[@MC-ik3zn]

What about gas pump on original from the car how to this one works with?

[@OldCrowsClassicCars]

The pump is a mechanical type, meaning it's run directly from the engine. There's a shaft from the pump that rides on a lobe on the camshaft. Not like most new cars that have an electrical pump inside the fuel tank

[@ppatel8774]

I have a 91 Chevy and I just put I new oem fuel pump and the gauge still reads full anything I should be checking ? Thank you

[@OldCrowsClassicCars]

I would remove the corresponding wire to see if the gauge goes to empty...or you could even remove the sending unit, and manually move the float arm to see if it moves the gauge. There's a way you can replace the float arm (and it's resistor) by a jar of water with salt to act as the resistor. That way you can test the gauge.

[@gilzz4600]

Will it works with stock sender?

[@OldCrowsClassicCars]

Depends on the unit....because they might not have the same resistance

[@kanaletumlinson]

Great video thank you! Even though the camera guys was F’n it up haha

[@OldCrowsClassicCars]

Hahah. Ya. If I fire the camera guy I will have no work

[@frankdavidson9675]

is both units american to match both have be the same country to test your sender disc wires if you have an ohm meter set on low ohms connect one meter lead to top connector of sender connect other lead to mounting plate move float arm back and forth it will read 240empty or 33 full you should be able swing float back and forth watch ohm/meter change to these #s --- you can not mix say japanese sender and american gauge ----will not work very this conn this way to test gauge 1 wire from mounting plate gauge mounting bracket the connect neg batt lead to same mounting now run a wire from center conn on sender to proper conn back of gauge now run plus battery lead proper conn on back of gauge now needle shoul follow you moving float arm up and down

[@OldCrowsClassicCars]

Yes, your correct, different gauges and sending units might have different resistance values. I bet you though that even within the same country they will make them differently the bastards. That's why it's usually best to buy them together

[@jorgesolis9535]

Bro what could be if my gauge start on the half mark when the arm's unit is on bottom ?

[@OldCrowsClassicCars]

sounds as though the gauge and sender are incompatible, if not, it must be bad resistor

[@ARC51bowtie]

What if my gauge is reading past full? Is it not grounded?

[@OldCrowsClassicCars]

If it's past the full mark, I'd say it's damaged for sure.

[@lancestrahm2362]

My gauge is always on full no matter what. Is it possible it's not the sending unit? I really don't want to drop tank and all of that lol

[@OldCrowsClassicCars]

It is possible. You have to test the gauge by itself as I did in the video, and you can also replace the sending unit by a jar.of water for testing purposes

[@tehzeebulhassan8547]

Please guide me with correct connections....

[@OldCrowsClassicCars]

you might also have switched one of the terminals around. Perhaps some gauges aren't labeled with the terminals. Also, the position of the terminals is NOT universal... for example, the sender might not be the left terminal on your gauge.

[@OldCrowsClassicCars]

Some gauges may possible have only 2 terminals, with the case itself being grounded. However this would require the positive terminal to be connected to the ignition switch or starter terminal and turn on and off.

[@berburuhewan6525]

@@OldCrowsClassicCars I need your help. Well, I've just bought a fuel gauge with 3 terminals. The problem is the terminals are not labelled. How can I identify which goes to ignition (+), ground and sender? Can we use a multimeter to identify? Or will I damage it if I just randomly connect it to a 12v battery and sender?

[@OldCrowsClassicCars]

@@berburuhewan6525 Your gauge may or may not be the same as mine. On my gauge, it's basically impossible to ruin the gauge, because there are basically only 2 terminals, a + and a - , and the 2 negative terminals aren't connected to each other so there is no way to cause a short on my gauge. BE CAREFULL! perhaps your gauge isn't the same as mine and you could possibly ruin yours! Please be careful as what I do to my gauge could possibly damage yours. unfortunately, there is no way to open these gauges without damaging them. To find the terminals, basically I find out by trial and error. I'd also check to see if one of the terminals is different than the other and just do a google search and see if you can find that info. Assuming your gauge is the same as mine, then from the voltage source: Connect the + to one terminal. Then connect the negative to another terminal. 1 of 2 things will happen: 1) Needle moves. Therefore one of the 2 terminals is the S while the other is the +. I'd start with the wiring shown on my video, as I imagine most gauges would be wired this way, with the S terminal at one of the side terminals. 2) Needle doesn't move. Therefore the terminals are + and - and the remaining terminal is the S. Then it's just a matter of reversing the terminals if necessary so that the - voltage source moves the needle when connected to the S terminal. As I mentioned in the video, there are 2 negative terminals and 1 that's +, because the S terminal is basically a negative terminal with variable resistance. Connecting the + and - terminals doesn't cause the needle to move, whereas if the S terminal and the + are connected, the needle will move. So basically connecting the voltage source to the terminals that don't cause the needle to move identifies the + and - with the S being the one remaining terminal. Reversing the terminals causes the needle to turn the wrong way I believe. Hopefully this helps!

[@berburuhewan6525]

Thanks a lot for the quick and clear reply.

[@crappienaterfishing1198]

???? What was that?

[@williambutler8624]

Great video, you explained everything very well, broke it down where you can understand how everything works, most of these videos you are more confused after you watch it, I have a 66 C-10, my gauge reads empty, I have tested sending unit, it works its 30 ohm, the gas gauge is new, when I unplug sending unit wire from tank it reads full, which most tests say your gauge works, ground at tank is attached properly, any advice on what could be the problem, SUBSCRIBED.

[@OldCrowsClassicCars]

Comments like these make it all worthwhile! I'm glad it helped! Does the gauge read empty when the float arm is raised? You could also look into the resistance (ohms) of the gauge...they kind of have to come in pairs, because different resistances, will cause problems like that. If you still need help, rewatch the video,and send me an email with your schematics. Also, you can easily test the gauge directly, by making a simple variable resistor from a jar full of salt water, and moving electrodes (such as 2 knives) close to each other . Let me know if you need help

[@jefferyyoung5401]

Variable!! SAY IT!!! VERY-A-BULL!!# SAY IT!!!! WTF MAN

[@pushpendratarana6347]

Plz. wire connection is properly not understand

[@OldCrowsClassicCars]

Could you be more specific? On the sending unit: + goes to + at ignition switch - goes to any negative/ground on the frame of the car S goes to sending unit( it only has 1 terminal) This provided your car is 12volts negative ground/frame. If it's from before 1960, it might be 6volts and + ground/frame.

[@PcDoc5897]

Fakin camera! :)

[@OldCrowsClassicCars]

hahaha. yes!

[@Palacios29]

My gage is always full

[@OldCrowsClassicCars]

If not caused by the symptoms I showed on the video, then it will be due to incompatible resistance (ohm values)

[@classic287]

My 97 Ford Ranger has a thing called “anti splash”, so the fuel gage doesn’t move back and forth when the gas splashes around in the tank. The gauge shows full all the time because that thing is burned out ☹️ Fuckin piece of shit 😡

[@OldCrowsClassicCars]

Yes, these gauges are garbage! I hate them too. The only decent gauges are the mechanical ones, I believe mandatory in small aircraft, but they're expensive, and the fuel has to be close to the gauge. I'm planning on building a mechanical fuel gauge and a mechanical temperature gauge, using the same principal operation as thermostats use.

[@jefferyyoung5401]

So brainiac, is that a rheostat or a potentiometer?

[@OldCrowsClassicCars]

Hahahah. Clever. I call it a variable resistor.

[@OldCrowsClassicCars]

check out these mechanical gauges: rochestergauges.com/product/6400/

[@frankdavidson9675]

where is your float dont look likey you have a float and arm conn you will never get a reading like that

[@OldCrowsClassicCars]

yes I do move the float, watch the rest of the video

[@Thecoachco]

Did I hear the F word?

[@OldCrowsClassicCars]

hahahaha. Those earlier days were tough....alot of stress

[@tehzeebulhassan8547]

Brother I am connecting battery+ve to - and battery -ve to ground... Sander, s S to meter, s S.... But there is no correct reading. Meter shows full... 😌

[@OldCrowsClassicCars]

Sorry, I just got this. That should be correct. Perhaps your sender or gauge is damaged. What happens when you move the arm on the sender? does it move the needle? when you disconnect the wire, what happens? I believe I show this in the video..it's long, but it shows answers the questions you're asking.

[@tehzeebulhassan8547]

Now if I connect. +ve of battery to - of guage and -ve of battery to ground of guage......... S of sender to S of guage. Then where I should connect other terminal - of sender....????

[@tehzeebulhassan8547]

Dear brother ur video is absolutely correct I just have ambiguity that where to connect - of sender unit...

[@OldCrowsClassicCars]

@@tehzeebulhassan8547 The sending unit itself should be grounded (connected to the body of the car, which is usually negative since the '50s. Glad to know it worked out!

[@frankdavidson9675]

you need two wires from sender to conn to s and gd on the gauge do not rely on gd of car body that sender is very sensitive must send only 33 to 240 ohms to gauge on american if its forien it will read 0 to 100 ohms some cars chasis read several hundred onms from one end to the other two copper wire that same distance will read very few ohms @@OldCrowsClassicCars

[@atibapa1813]

this is a 5 min video

[@OldCrowsClassicCars]

someday, I'll get an editor, but you're right