'91 Volvo Wagon headlight & overdrive issues

Two issues with my 1991 Volvo 240 wagon, automatic transmission.

1. My headlights are stuck in high-beam mode. I think I’ll try to replace the Highlight Relay first?

2. Automatic transmission doesn’t switch beyond 3rd or 4th gear. It doesn’t slip, transmission fluid is filled, overdrive button has no affect, and fine for local driving, but need to fix for highway driving. Volvo has occasionally idled really low and stalled out a few times. Could this also be Overdrive Relay replacement needed? Any help, info would be so greatly appreciated!