Hello All. 1986 Volvo 240 sedan stick shift(4 speed plus overdrive). I disconnected the negative battery cable for about 10x minutes. Now my dashboard shift indicator light doesn't fully work. That is yellow light on lower right corner which tells you when its time to shift. Although not essential to have I kind of liked it. Now It only works when in 4th gear. It lights up to tell me to engage overdrive. This is only time it works. Not 1 to 2, or 2 to 3, or 3 to 4. Why did this happen ? What can I do to make it fully functional again ?? Thanks very much. P.S. - Everything else on dash & elsewhere is fine.