Fellow Stovebolt members, maybe you can help and maybe you've heard this problem a dozen times. Anyway, here goes. I have a 49 Chevy truck that was converted to 12v. I replaced my old fuel gauge with a new 12v one, and I have wired it correctly from the gauge to the sending unit and the other wire to the ignition. I also have the sending unit grounded to the frame. Also all new wiring. I start up the truck and the gauge doesn't move (stays on empty). When I Disconnect the sending unit wire at the sending unit the needle on the gauge jumps above full. What am I doing wrong or could I need a new sending unit. I checked and it is a 30ohm sending unit. I'd appreciate your advice.
Last edited by roberts49chevy; 04/16/201811:34 PM. Reason: spelling
Gauge part # GTS4743 from Brothers. Original style sending unit. Yes 30 OHM. No gauge is not wired backward, I'm sure. Sender wire itself is not grounded. Ground is at sending unit, and metal housing (gauge case) where fuel gauge (and other gauges) are attached. Sending unit grounded near negative battery terminal on frame.
Ok I have the 12v at the gauge terminal connected. I removed sending unit wire (at the sending unit) that goes to the gauge. Yes it reads max full. Connected the sending terminal to ground (I used the ground wire from the sending unit). Nothing happened.
Gauge part # GTS4743 from Brothers. Original style sending unit. Yes 30 OHM. No gauge is not wired backward, I'm sure. Sender wire itself is not grounded. Ground is at sending unit, and metal housing (gauge case) where fuel gauge (and other gauges) are attached. Sending unit grounded near negative battery terminal on frame.
Ok I have the 12v at the gauge terminal connected. I removed sending unit wire (at the sending unit) that goes to the gauge. Yes it reads max full. Connected the sending terminal to ground (I used the ground wire from the sending unit). Nothing happened.
What do you think?
You did answer them. You are correct.
My post said I "rebooted" my effort to help. My post (now deleted) said I could not find that gauge PN on Brothers website. (GTS4743). I said that is a Gas Tank Sender number and is also probably 4753. Read and understand your post has bad info. I try to double check all PO info to be sure of my advice (part numbers, ohms, voltage). I asked if you put in a voltage reducer to a new 6V fuel gauge (whatever the PN). And I posted a video link to a How-To regarding fuel gauge and sender testing. The video was by a very respected wiring harness and accessories company called American Autowire.
You say you don't understand and want other advice. If you didn't understand any of that, fair enough.
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn
Sorry for my frustration. I understand now. Brothers lists the prt # on invoice and in catalogue as GTS4753. Anyway, it is 30 OHM. The truck is 12 volt, as is the new gauge 12 volt. Why would I need a voltage reducer?
"Why would I need a voltage reducer?" So you do not "fry" the fuel gauge. Some people say they/you do not need it. Most people who do not use it end up losing the gauge. It is much cheaper than buying a used/new gauge.
It goes on the "input" side of the gauge ("behind" the Empty marking on the gauge). It does not go on the side of the gauge where the sender wire is attached.
OK, one last time. Read this very carefully. I ask you what the GAUGE parts number is. You keep giving the SENDER part number. What is the GAUGE part number? You seem to be confused about all these simple questions. You don't seem to understand we can't fire off a bunch of "could be this or could be that" without making sure of the parts you have. Sometimes posters think they know what they are doing and get insulted by questions. But if it's the gauge or sender or something is wired wrong or incompatible parts or wrong parts and we have to figure it out from our house. We are not there. We can't trust everything because obviously there is a problem. Something is not right. We only have questions at first, not a bunch of guesses.
As Tim and I say, you may need a voltage reducer. You ask why. If you give us the gauge part number we can check to see if it's a 6V or 12V. That's why I have asked 4 times for the part number. If you are assuming this or that and making a mistake, we have to catch the mistake by searching part numbers an so on. You can't keep saying you did everything right and you have the right ohms and voltage. Someone HAS TO CHECK your work and your parts. That would be us. What is the part number of the GAUGE and where did you get it? I don't see a 12V gauge at Brothers. Don't just keep saying everything is OK, it's 30 ohms, it's 12V, it's wired correctly. People won't find a problem if they keep assuming. You are frustrated by just answering questions. This time, LOOK AT THE VIDEO.
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn
I mentioned, and he confirmed, GTS4753. It is a sender. It was a typo but I didn't ask the PN of sender. Waiting to hear the PN of the gauge that he purchased and what vendor. Same PN for 6 and 12 volt ? Sure like to know the reason they did that. One gauge accepts both voltage? Some folks on Stovebolt have said they operate a 6V gauge on 12V, no reducer. I think I read that somewhere? The 12V Conversion Tip says use a reducer. I gave him some tests that I am now not sure of, so posted the video link to reboot testing procedure. I apologize to Robert for the initial test advice.(removed)
The funny thing about all the reading I did on testing is that some describe a test and say if it does this and that, the gauge or sender is bad. Some tests say if it does this or that, the gauge or sender is good. So I gave up and posted a Video from a reliable source. Some don't even say which end of a wire to disconnect and touch to something. If I ever write up a tip it will be crystal clear. If it does this it's good, if it does that it's bad............
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn
Tim: Seems like I remember it's more of a how to wire it up than a troubleshoot. Could be my computer but the links give a 404 error. The video I posted should be very helpful to the poster.
Are you kidding? Are you OK? PM me if you are not OK.
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn
I mentioned in a previous message I have installed a new 12 v fuel gauge. It is marked 12v on the back if the gauge. I've connected the terminal marked "ign" to the ignition. I connected the terminal marked "sender" to the fuel sending unit at the gas tank. Ok now I connected the ground wire from the sending unit (on one of the screws that you attach the sending unit to the tank) to the frame for a good ground. I don't think I need a voltage reducer because its all 12V - Gauge and sender. All I'm asking if I run a test where I disconnect the wire at the sending unit, the gauge goes to full max. Does this mean I need a sender?
This is what I get when watching the video I already posted; To answer your specific question, YES. Video says if gauge always reads empty and disconnecting sender makes it go to full, gauge is good and sender is bad....or a short in sender wire.
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn
Just to update. All fixed. the wire from the sending unit to the gauge was grounding out somewhere. I ran a new wire and the gauge went to 3/4 full which is what i had in the tank. Thanks for your help.
