Speedometer Dead

[scot850]

I linked the owners manual earlier above. It gives the layout of all the warning lights, even the ones that are considered options.

ABS warning light is the furthest RIGHT and the top row. It should glow orange.

The TRACS is middle light on the RHS on the lower row. If I recall it should glow RED. Both should come on when the key is moved to the 2nd position. If you have Tracs (I thought you said your car had it) then there is usually an OFF/ON switch on the row to the right of the steering wheel. It should be the first switch from the steering column. Strangely, my car has TRACS but it had no option to switch it off. The cable was there but no button.

Again, look at the owners manual on pages 18 and 19 for the info on the warning lights.

Neil.

[MrAl]

I linked the owners manual earlier above. It gives the layout of all the warning lights, even the ones that are considered options.

ABS warning light is the furthest RIGHT and the top row. It should glow orange.

The TRACS is middle light on the RHS on the lower row. If I recall it should glow RED. Both should come on when the key is moved to the 2nd position. If you have Tracs (I thought you said your car had it) then there is usually an OFF/ON switch on the row to the right of the steering wheel. It should be the first switch from the steering column. Strangely, my car has TRACS but it had no option to switch it off. The cable was there but no button.

Again, look at the owners manual on pages 18 and 19 for the info on the warning lights.

Neil.

Oh yes i see now, thanks.

Ok, so the ABS light never lights up, and the Tracs light never lights up. They also do not light when the engine is running either.
I assume it has Tracs because there is a Tracs button.

How hard do you think it is to test the bulbs?

I looked at some analysis scanners and wow some of them are as high as $5000 USD.
The cheaper ones do not say exactly what they test for when it comes to the ABS. They state "ABS" but that's all.

What seems strange to me is that it is unlikely that all four ABS wheel sensors would go bad at the same time, and with three still working i would think they would be smart enough to allow the speedometer to work for now. I wonder if it could be the ABS module.

[scot850]

The fact that they don't come on at all means either the bulbs have failed or the previous owner removed them. To access the bulbs you have to remove the dash pad and then un-clip and remove the speedo binnacle. The bulbs are just twist in holders.

If you are not comfortable tackling that on your own car, it is where I always suggest going to a scrap yard and practicing on a junkyard car.

It is not particularly difficult other than the passenger airbag disconnect. With that you just squeeze hard on either side of the connector at the left end on the horizontal plain and then it will pull out to the left.

At this point I will suggest that the ABS module is bad which typically happens. A junkyard ABS module is not usually worth it as they are usually bad.

Neil.

[MrAl]

The fact that they don't come on at all means either the bulbs have failed or the previous owner removed them. To access the bulbs you have to remove the dash pad and then un-clip and remove the speedo binnacle. The bulbs are just twist in holders.

If you are not comfortable tackling that on your own car, it is where I always suggest going to a scrap yard and practicing on a junkyard car.

It is not particularly difficult other than the passenger airbag disconnect. With that you just squeeze hard on either side of the connector at the left end on the horizontal plain and then it will pull out to the left.

At this point I will suggest that the ABS module is bad which typically happens. A junkyard ABS module is not usually worth it as they are usually bad.

Neil.

Hi,

Oh wow, yes that sounds like a lot a lot a lot of work. Beam me up Scotty

By "dash pad" i guess you mean the section that is the very top of the dash board. I might be able to do that, but i would worry about being able to get it back on right.
Not sure what the "speedo binnacle" is though.

The ABS module looks hard to get off i watched Roberts video. It's a strange place for something like that too. Have to be able to get down under it to remove the screws, with a special bit. The special bit no problem, but how the heck do you see the screw heads, with a mirror maybe?

I guess i am losing hope in being able to get this fixed by myself.

I am a good judge of car speed without looking at the speedometer i found, for speeds 20 to 40 or so.
The GPS speedometers look very interesting too, and don't rely on the car guts to work. There are a million different kinds now too, even one for the Arduino. Maybe i could just use one of those for a while. I would have no car odometer to keep track of the mileage of the car though, unless i got one that also had a long term odometer function. Would be hard to explain to someone who asked what the mileage of the car was though, have to add the current to the new readings to get the total.

[abscate]

a single ABS sensor failure can take out the speedometer on a V70 at least.

Grunhilde the 1998 has the left front sensor inop and no speedo

[scot850]

This is one of those cases where diagnostics may be of benefit. Not sure how good it may be as it will likely say speed signal missing. Abscate is right that a bad sensor will kill the system. If you go to Mid-West ABS website, Matty has a diagnostics process. This includes resistance testing the sensors. This would eliminate them as an issue or prove them an issue. Strangely front left as mentioned can be an issue. Did you try wedging anything between the harness and the abs unit?
ABS module swap is tricky as you work from the top using touch. I always find one bolt head is bad but check with a mirror on a stick.

Neil.

[MrAl]

a single ABS sensor failure can take out the speedometer on a V70 at least.

Grunhilde the 1998 has the left front sensor inop and no speedo

Oh thanks Steve that was one of my major questions.
Now to figure out which one.
The Obd2 speedometer signal is dead too.

[MrAl]

This is one of those cases where diagnostics may be of benefit. Not sure how good it may be as it will likely say speed signal missing. Abscate is right that a bad sensor will kill the system. If you go to Mid-West ABS website, Matty has a diagnostics process. This includes resistance testing the sensors. This would eliminate them as an issue or prove them an issue. Strangely front left as mentioned can be an issue. Did you try wedging anything between the harness and the abs unit?
ABS module swap is tricky as you work from the top using touch. I always find one bolt head is bad but check with a mirror on a stick.

Neil.

Hi Neil,

I didnt try anything to fix it yet except:
Looked at the dash lights which may be inconclusive, and
checked the Obd2 speedometer signal and that was zero for any speed.

Did you mean wedging on the abs wheel unit?

[scot850]

No, jamming a piece of cardboard between the ABS module and the end of the ABS pump. I sent you a link earlier about someone who had done that and explained how he did it. Check that out. All it does is if the circuit board in the ABS module has fractured the connection, which is the standard failure mode, and pushes the wire connections higher onto the contacts on the board. It is not a long term fix but again if it works then at least you would know the issue that needs fixing. You will obviously only know it has worked if the speedo starts reading again. However, if the bulbs are out naturally you will not know if it is fixed otherwise.

Neil.

[MrAl]

No, jamming a piece of cardboard between the ABS module and the end of the ABS pump. I sent you a link earlier about someone who had done that and explained how he did it. Check that out. All it does is if the circuit board in the ABS module has fractured the connection, which is the standard failure mode, and pushes the wire connections higher onto the contacts on the board. It is not a long term fix but again if it works then at least you would know the issue that needs fixing. You will obviously only know it has worked if the speedo starts reading again. However, if the bulbs are out naturally you will not know if it is fixed otherwise.

Neil.

Hi Neil,

Oh yes i forgot about that one.
I might be able to try that today.

Thanks much, hope it works.
I guess that would mean the connector solder is bad. I could easily fix that if i could get the module off.