Fuel gauge not working

CraigP83 · August 14, 2012, 10:03:45 AM

While out on the water sunday my fuel gauge stopped working. At one point I looked at it and it was pegged all the way to the right way past "Full". Then when I looked again it was pegged all the way to the left way past "Empty". Now I can get any movement out of it at all, Switched to the other tank and still wouldn't budge. Anybody have any trouble shooting ideas? Its my goal this week is to get it working again so I don't accidentally run out of gas while fishing.

EDIT: 1998 Ranger Comanche DVS Special

Mike Cork · August 14, 2012, 10:12:32 AM

Well from the sounds of it there is a short. Look at the connections on the back of the gauge and make sure they are tight and not touching each other. Then do the same with the sending unit on the top of the fuel tank. Most times that's all it is.

From there it's tricky, you'll have to ohm out the system and not knowing what kind of resistance is involved based on the current level of the tank? But that would be more for accuracy. Check your tank sending unit and then the Gauge, again I don't know what the reading should be but when you look at the wires you should be able to tell what is ground and what is sending unit, just make sure you don't have a direct short inside either component. Then it's time to Ohm wires from the gauge to the tank, if there are now opens or direct shorts, ohm back the other way, from the tank to the gauge.

BassBUFF · August 14, 2012, 04:15:29 PM

Mike is on the right track. If you have two seperate tanks that means you have two seperate sending units so the likelyhood of them both going bad is low. The gauge and/or wiring near it is the common denominator. Let us know what you find.

CraigP83 · August 16, 2012, 08:32:19 AM

Ok, guys...

I crawled under the dash last night all the wires to the switch and to the fuel gauge are securely attached. It is a dual tank boat, and when I switch from portside tank to starboard the gauge does not move one bit. What are the odds it could be the gauge itself, or even a blown fuse?

EDIT: I dont know were the sending units are on my boat or how to access them. It would be worth checking the wires on them too, but like BassBUFF said could both sending units have gone bad at the exact same time?

Mike Cork · August 16, 2012, 10:24:17 AM

Highly unlikely that both sending units are bad, and even more so that they went bad at the exact some time. See if you can find where the wiring becomes common (it may not there may be straight wires to the sending units to the gauge or switch between them.

Looking more like the gauge at this point. Could be a switch that is shorted and not working properly. I'd have to see the diagram on this one? There are a couple different ways to set up the wiring. But no matter how I lay this out in my head the switch is also a common denominator, I like a bad, broke, or stuck switch over the gauge. Switches are cheap too. You could remove the switch and determine how to bypass it to get a reading off of one of the tanks

to see if the gauge will work then.

I'm not real familiar with dual tanks. The one boat I had it was a manual valve and there was not gas gauge. So do you have a manual valve to switch tanks and an electrical switch that is separate that checks level?

CraigP83 · August 16, 2012, 10:40:02 AM

Yes its a manual valve that switches tanks. Then the switch itself just allows me to switch the gas gauge from starboard or port to check the levels.

I didn't think about the switch being bad...

Quote from: Mike Cork on August 16, 2012, 10:24:17 AM
But no matter how I lay this out in my head the switch is also a common denominator, I like a bad, broke, or stuck switch over the gauge. Switches are cheap too. You could remove the switch and determine how to bypass it to get a reading off of one of the tanks to see if the gauge will work then.

I'm going to look again tonight I think its just a few spade connectors attached to the switch, when you say there is a way to "bypass" it.. do you mean just touch the wires together to "jump" past the switch?

Mike Cork · August 16, 2012, 12:45:09 PM

Yep, the most basic would be just three wires. Two going to the switch (from the sending units) and one leaving the switch to the gauge. You should be able to turn power off, connect one of the sending unit wires to the gauge wire. Turn power back on and Gauge should work.

BassBUFF · August 16, 2012, 01:40:15 PM

The other side of the coin would be a missing or loose ground wire. I'm betting the gauge went Tango Union. But do as Mike suggested and bypass the switch first.

CraigP83 · August 17, 2012, 08:10:27 AM

"Jumped" the sending unit wire to the fuel gauge wire (with a fish hook, lol) and turned the power on. No movement what-so-ever. I'm thinking it must be the gauge. Ill keep you guys posted on what I find, thanks for all the help

BassBUFF · August 17, 2012, 03:30:54 PM

I'd agree.

Mike Cork · August 18, 2012, 09:38:35 AM

Yep if the connections are tight on the gauge (which you've already checked) doesn't leave much else... Keep us posted.

CraigP83 · August 27, 2012, 06:49:04 PM

Just giving you guys an update.. The new gauge came in the mail and I got a chance to throw it in. Im now getting a reading on both tanks!

Thanks for helping me troubleshoot Mike and BassBuff

BassBUFF · August 27, 2012, 07:17:49 PM

No problem!

Glad you got it fixed and THANKS for following up to let everyone know!

Mike Cork · August 28, 2012, 08:50:35 AM

Good deal

thank you for the follow up report.