gas gauge jumpy

[oddengineer]

Been having some issues with my gas gauge needle jumping around while the car is on. Ive read a few posts and a lot are saying the grounds are bad however ive since redone the grounds and issue continues. I also redid the power wire coming off the indicator bulb holder and ran a external wire from the sender to the gauge its self to test if the original wire may have had a broken connection and the same issue. If I remember correctly even after replacing the sending unit in the tank I had the same issue going on. Any suggestions on what else it could be? This is a 12v gauge also I know its not the original one being my bus is a 62 and it should have been a 6v but everything is 12v now. Could it maybe be the gauge is bad or even the sending unit even though it was new at the time I installed it about 2 years ago?

[BarryL]

[oddengineer]

The sending unit is grounded from one of the bolts on top to the body then from the gauge it has a prong labbled 31 which is part of the housing and that's grounded to the body as well I do not have the back clamp however for the gauge however but that shouldn't matter should it if the body of the gauge is grounded from that prong?

[BarryL]

[oddengineer]

I know this is not correct for the year but it is a 12v gauge

[BarryL]

OK, yeah, that should be a good ground. Weird that it does it with two different senders.

[oddengineer]

Ya I'm wondering if the gauge it's self may be bad or something even when it's full gas it has a wobble in the needle

[oddengineer]

also while we are on the subject of wiring im a little confused on the wiring diagrams they have in the technical section I see the wiring for a 61 and a 63 however for the 62 it shows a drawing for a 62-65 drawing and there are things that I don't have in the bus that are in those drawings or are slightly different in coloring for instance on the blinker switch board it says there should be a green/white/black wire but all I see is a black wire from that housing but the rest of the wires are correct so I just assumed that is the wire. Just strikes me as odd that the diagrams for 61 and 63 are in color and the 62 one looks different

[BarryL]

[Eric&Barb]

Well you have a K. Ghia gauge for about a 1970.

Might be the cheap terminals you are using on the wires that is causing you the problem. At least remove the plastic covers, so you can solder and heat shrink for a gas tight connection between the wire end and the terminal.

Or get the proper factory style crimper tool and the brass uninsulated terminals as were installed at the factory.

https://www.thesamba.com/vw/forum/viewtopic.php?t=338938&highlight=brass+connector+crimper
_________________
In Stereo, Where Available!

[oddengineer]

I'll try the terminals however I don't see that as the issue but doesn't hurt to try someone was telling me try making a better connection on the ground of the battery as well as the tranny strap might try that first..... the reason I was asking about the green white black from the turn signal is because my wiring does not have this color nor do I see that wire anywhere just the black wire from the turn signal. But all 3 of those diagrams show a slightly different wiring pattern just fine it strange they have a 61 diagram then it goes 62-65 diagram then a 63 diagram and nny bus is a Nov. of 61 vin

[BarryL]

[oddengineer]

I would assume so seeing as to how the other colored wires are all the same just that one wire is a different color than what is in the wiring diagram. However my blinkers work fine now no more hitting the brakes and they get cancelled out who ever wired it before must not have followed the diagram at all and just put stuff where ever the only thing I noticed is they blink with the key off but that's how it's wired up on the fuse box. Still chasing the gauge issue though going to try and run a direct ground from battery see if that changes anything possibly a direct power too if need be and if not a new sender then finally gauge. Process of elimination at its finest

[oddengineer]

so I broke down and ended up buying a new gas gauge from ISP and I have to say well worth it. After talking to the guy about the issues I was having and doing the things he suggested trying before with no change in the gauge being jumpy I was telling him about how Eric&Barb mentioned that the gauge was from a 70 ghia and he said that was the issue the way the ohms read were different supposedly. Installed the new one and presto gauge went up and wasn't bouncing around stayed right at where it landed after going up slow unlike the last gauge that jumped to the area. All my wiring appears to be working correctly now however I had one last question about the dash panel. The bus is a 62 and I have 3 holes where switches would go. I assumed it was for a hazard switch but there is no spot for the hazard light on the left side above the wiper switch what is the third hole for?