Unfortunately, these are all things that are out of my comfort zone/level of expertise.Did you find what the issue was with the cruise control and signals?
There may be a connection here between this problem and your other ones.
Check your battery output. Amps, not voltage. I've had batteries show 12.4 volts and only supplying 75 amps. Check your cables from the battery to block and all the ground cables running to the body and from the harnesses to the block and firewall.
Then check your alternator output with loads.
After that, get into the sensor outputs.