I'm finally replacing the broken gas gauge in my truck , and ran into a problem.
I installed the gauge but it didn't work, so I found a thread here that mentioned the little plate on the back of the gauge has to ground on the gauge housing. I did that, and now the gauge kinda works.
If I take the lead that goes to the sender and take it off the sender, the gauge shoots way past "F". If I than ground the wire, the gauge weakly attempts to move the needle back, but will either not move it, or move it back only a tiny amount. I made sure I'm using a good ground when I do that.
What would cause something like that? I made sure all my connections are tight and the gauge is a new 12v unit from classic parts. This is going in a '53 chevy converted to 12v.
"If I take the lead that goes to the sender and take it off the sender, the gauge shoots way past "F"."
If your needle goes to full when you disconnect the sender, that usually indicates that the gauge is good.
"If I than ground the wire, the gauge weakly attempts to move the needle back, but will either not move it, or move it back only a tiny amount."
What wire are you grounding? The wire from the gauge to the sender (dsconnecting the wire at the sender and grounding that end of the wire)?
Someone else might have advice about grounding the gauge itself.
It looks to me that you might have a bad sender, or, a bad tank-to-ground connection. I have seen people place a ground wire from a sender-to-tank bolt to clean metal on the frame/cab/etc.
If I understand you correctly (I watched your video), try this. You need to ground the gas gauge lug or terminal, not the wire going to the sender. So, with three terminals on your gauge, 1. 12 volt, 2. ground, and 3. sender hooked up correctly, remove the sender wire from the terminal and full it goes. Remove the wire and ground the terminal and empty the gauge goes. Now the hard part...the above is for a zero to ?(let's say 90 ohms) sender. Some senders are ?(let's say 90 ohms) to zero, and some are like my Packard 72 ohms to 10 ohms. Do you have the correct sender for your replacement gauge? If that ain't enough, some fuel gauges are not fed a steady diet of 12 volt. They use a device that puts out a voltage pulse, somewhat like a blinker can. Sorry if I stirred up the mud.
Ferndale,I posted the comment on the grounding plate..I bought a 12 volt gas gauge from classic also...that is where I got the info on making sure I have the gauge back making contact with the housing surface and the tabs that hold the housing onto the dash are solid. I only had 2 posts on the back....Sender/sensor and IGN ( Came with a small cardboard sign ). I know I have read on this site that there is a way to check your gauge...It had alot of hits with good advise..step by step instructions...try and search the tech tips....or beg more and someone will take pity and not let you struggle( thats what they make me do )ha,ha,ha...Hope it all goes well,I'm sure someone will have the answer for you...so far it's been a great resource for me. ps..I'm not finished with my wiring so I don't know if mine is hooked up correctly either..... Enjoy
After reading DADS50's post, I see I need to clear my post up somewhat. The gauge may not have a ground terminal, so as DAD50 and others have stated, you need to make sure the gauge has a ground or common and also your sender.
It turns out the gauge was bad. I checked everything like you said, and still had the problem.
I found an old gauge in a pile of parts and I tested it and it worked. I had tested it wrong a year ago and never got around to throwing it out, good thing!
and never got around to throwing it out, good thing!