ABS Fuse affecting Speedometer?

[kgolden5901]

Ok, so the other day my wife calls me and says her speedometer isn't working and that the gas gauge is going up and down from full to empty. So after getting home I take a look at the car. Now I build and fix computers NOT cars but I can navigate my way around the fuse box and stuff. Anyway, i noticed the 7.5amp32v fuse is blown and the card says its the ABS fuse. There was never any ABS light on in the car. I replaced the fuse, test drove the car and VIOLA speedometer was working and the gas gauge was fine. She just called me saying it was happening again. Any ideas? Thanks

[MyOtherRidesAVette]

First thought, VSS (vehcle speed sensor) which inputs to many functions through the ECMs, but no clue what would be blowing the fuse. To my knowledge the only thing that blows a fuse is an overload or a short. Solving an issue that a blown fuse is part of isn't resolved by replacing the fuse.

MORAV

[kgolden5901]

my reasoning for only changing the fuse was because the fuse appeared to be the original in the car. ITs a 1998 so I figured the fuse could be just old. I am curious though as to why the fuse change of the "ABS" is affecting the speedometer. I can't find any documentation that would clarify the issue.

[MyOtherRidesAVette]

The VSS is a component of both the speedometer function and the ABS function. It actually provides information, through the ECMs for many things, which is why I suggested this might be the source of the problem. Perhaps not the VSS itself being bad, but a short in that specific circuit. Possibly at the VSS connection. I might also suggest that age will virtually not affect a fuse, anymore so than a wire.

M.

[mlt]

Originally Posted by MyOtherRidesAVette

The VSS is a component of both the speedometer function and the ABS function. It actually provides information, through the ECMs for many things, which is why I suggested this might be the source of the problem. Perhaps not the VSS itself being bad, but a short in that specific circuit. Possibly at the VSS connection. I might also suggest that age will virtually not affect a fuse, anymore so than a wire.

M.

You should be more specific which one of VSS. Some rodent bit a cable of mine G68 VSS so car didn't shift gears and vehicle speed reading was 0 from OBD-II, but the speedometer itself was working just fine!

[MyOtherRidesAVette]

Originally Posted by mlt

You should be more specific which one of VSS. Some rodent bit a cable of mine G68 VSS so car didn't shift gears and vehicle speed reading was 0 from OBD-II, but the speedometer itself was working just fine!

I'm sorry, I should have looked it up. Which I have now done. [G22] Speedometer Vehicle Speed Sensor. I have not looked to see if this is the one used by the ABS system, but truthfully I was not aware, other that the wheel speed sensors [G44] [G45][G46][G47], that there was more than one, and obviuosly the speedometer vehicle speed sensor is not one of those.

Sorry, I can't get the pics for the hatchback to come up, But the location should be the same.

M.

[kgolden5901]

great pictures. I will check it when I get back to town. I will be traveling and I will take a look on Sunday and let you know what I find. Again THanks

[MyOtherRidesAVette]

Originally Posted by kgolden5901

great pictures. I will check it when I get back to town. I will be traveling and I will take a look on Sunday and let you know what I find. Again THanks

It's probably not that big of a deal, the fuse has no doubt blown again, so no further damage can be done, she just needs to be aware the ABS system will not function properly. If you need more help, I'm usually around here early and late, real late a lot of the time, and I have both the paper Bentley Service Manual and the DVD-ROM Repair Manual. Btw, I didn't take those pics, I pirated them from my Bentley DVD.

M.

[kgolden5901]

I have discovered that it is not the ABS fuse, but the instrument cluster fuse. Maybe I have a wire bad on the back of the speedometer

[MyOtherRidesAVette]

Originally Posted by kgolden5901

I have discovered that it is not the ABS fuse, but the instrument cluster fuse. Maybe I have a wire bad on the back of the speedometer

Ouch! What is the fuse position, so I can do a little research?

Forget the fuse card, here is a much better identifier, each has info the other doesn't (go figure), and printable -

Bentley Fuse & Relay Panels
Service Manual
http://newbeetle.org/forums/attachme...ice-manual.pdf
Repair Manual
http://newbeetle.org/forums/attachme...air-manual.pdf

M.