Problem: Auto tranny, overdrive light illuminated only after early morning cold start. It doesn't do it from cold start later in the day. After starting, other ignition lights go off but overdrive light about 80% illuminated. Push overdrive switch and light comes to full bright. While light at 80%, fuel guage and speedo don't work but do as soon as overdrive switch pushed.

Car's had other cluster/electrical gremlins and after replacing ignition switch and head light relay from P&P, gremlins disappeared for 6-8 weeks but now back with overdrive light/non working speedo/guages gremlin. On slim chance there was problem with voltage regulator, pulled cluster yesterday pm and swapped regulators. No problem with late day start and everything working after swap; but, problem back again this morning. Wife drives this car and tells me if overdrive light on when she leaves, alternator light starts flashing a few miles down the road but does not stay on. Alternator brushes almost new. Could cold solder joint in overdrive relay cause this? Bad connection or intermitent ground?

Why does it do it only upon cold start in the morning but not later in the day.

TIA for ideas.

Steve in Charlotte, NC 84 240 5-sd w/ 350+k still has original u-joints, 89 240 auto 221k but has gremlins. Garaged 940 needs engine.