Overhead compass always displays CAL

[96eb96]

I'm wondering if the compass failed. This isn't really related to the overhead message center display problem.

I've tried driving in circles and it is not going off. It does not show directions when you drive in the circle. In the past and on other cars it would usually calibrate with one rotation.

When the compass powers up it show NW, NE (or some other wrong direction) then just CAL with no direction.

Anyone ever have this? It don't seem to be very common.

 

[J_C]

There's some info in the following post, don't know if it applies to yours being a few years older or not:
https://www.explorerforum.com/forums/showpost.php?p=441475&postcount=5

According to my owners manual map (for a '98 though), Albany would be zone 12. The '98 owners manual also reads a little different than the post I linked above, reads:

"Press and hold the MODE control
until VAR appears in the display,
then release. The display should
show the current zone number.

Press the MODE control until the
desired zone number appears. The
display will flash and then return to
normal operation. The zone is now
updated.

Compass calibration adjustment

Perform this adjustment in an open
area free from steel structures and
high voltage lines:

• Press and hold the MODE control
until CAL appears in the display
(approximately eight seconds)
and release.

• Drive the vehicle slowly (less
than 5 km/h [3 mph]) in circles
until CAL indicator turns off in
about 2–3 complete circles."

You might want to get your vehicle year owners manual PDF, but it reads pretty much the same as above.
http://www.fordservicecontent.com/Ford_Content/catalog/owner_guides/96expog1e.pdf

As far as what happens if it breaks somehow, I don't know. It looks like the entire overhead module is replaced as one unit, though if there's a broken solder joint or something in there that you can find...

It would probably be shocking what a dealer charges for that if they even sell them. I'd get one from a junk yard if all else fails but they're around $50 on eBay. It's a shame that they have that vacuum fluorescent display in them instead of LED, as that means all of ours are going to burn out someday.

 

[96eb96]

Thanks, for the info.

I tried setting the VAR and going in slow circles, both directions. I'll give it another try. Usually though if all is working two rotations max is all you need.

There are two sensors on the board mounted at 90 deg angles, I'm thinking if the solder is bad on one of those it will never get the right signal and always ask you to calibrate. From the research I did this don't seem like a common failure mode.

The other thing in the manual talks about demagnetizing the vehicle with those old school CRT demagnitizers, doubt those even exist anymore.

 

[J_C]

It could be solder on the sensors themselves or another portion, or at this age if there are electrolytic capacitors they may have degraded enough to not keep the processor stable... at least I assume there's some kind of processor but I've never investigated electronic compass design.

 

[96eb96]

It could be solder on the sensors themselves or another portion, or at this age if there are electrolytic capacitors they may have degraded enough to not keep the processor stable... at least I assume there's some kind of processor but I've never investigated electronic compass design.

There are actually two designs, I assumed there was one before I took mine apart. I have the earlier one on the left. I think 98+ has the newer design, which tends to have the resistor issue. The newer design definitely cost less and minimizes components. The compass sensors are also solid state.

 

[J_C]

Those two look fairly interchangeable, the shape and dimensions I mean. Can you tell if they really are to the extent that people could choose either one as a replacement?

 

[jimmyznutz]

Those two look fairly interchangeable, the shape and dimensions I mean. Can you tell if they really are to the extent that people could choose either one as a replacement?

They are essentially the same. There is a bit of difference in how the boards and displays are mounted.