Ninth gen/E12 (2002) speedometer issues on sunny days

[garlicenjoyer16]

Hi everybody! I have a peculiar issue with the speedometer on my ninth generation (E12), pre-facelift, 2002 Corolla hatch.

While the speedometer works as normal on most of the time, it malfunctions under very specific circumstances. On sunny days, if the car is parked directly in the sunlight and does not move for at least a day, the needle will stay at 0 the first time you drive it. This has been the case for months. Previously, the issue would resolve itself within a couple of minutes; the needle starts moving from 0 while you're driving, causing it to be off by the speed you were doing at the time (i.e 30 kph off if it fixes itself while you're doing that speed). Coming to a standstill and restarting the car 'recalibrates' the needle, and the speedometer works as normal from there on out.

Recently, however, it has taken longer and longer for the issue fix itself. Last week, it took nearly 20 minutes for the needle to start moving. This indicates that the problem seems to be getting worse. 

Bizarrely, the issue seems related specifically to sunlight, rather than temperature. The speedometer keeps working as normal on a warm but cloudy day in August, while it malfunctions on a relatively cold but sunny day in March. 

The car works perfectly otherwise - other people experiencing speedo issues also report other issues such as engine lights, which mine doesn't have. The only other problem I can think of is that the outside temperature reading on my onboard computer doesn't work: it permanently thinks the outside temp is -30 degrees.

Does anyone know what could cause this problem?

[Mooly]

1 hour ago, garlicenjoyer16 said:

the needle starts moving from 0 while you're driving, causing it to be off by the speed you were doing at the time (i.e 30 kph off if it fixes itself while you're doing that speed).

It sounds a bit strange. Not quite sure what you mean by 'causing it to be off by the speed you were doing at the time'.

The only things I can think off (and some of what you say suggests it's not this) would be the pointer physically sticking be to heat/expansion.

If the temperature gauge has worked in the past then it might be worth looking at that first as it could lead to a common cause. Check any wiring ground points under the bonnet that the temperature sensor may go to. The sensor is often right at the front, in front of the radiator and A/C condenser. 

 

[DerekHa]

Hi Marcel, just a suggestion!

Is it possible the needle has become stuck just underneath the little pin that sits next to the zero on the speedo unit or even got stuck on the same pin?

You may have look very carefully and close  up at the speedo to see where the needle is sitting. If this is related to sunny days I guess it's possible for the needle to warp, twist or move having bee heated enough to allow it go past that little pin which is the stop point normally for zero.