Cruise control and wiper issue

[87Skier]

Just bought an 89 suburban and have been troubleshooting some issues.

The cruise control system doesn't work at all. I replaced all the vacuum hoses going to it, but have had no luck with it.

The windshield wipers only work in certain modes. If I try the mist setting it will stop as soon as the switch is released. The windshield wash works fine. None of the intermittent modes work. Slow speed and high speed work fine.

Do you guys think these issues are related or not? I'm thinking its the control arm, but I don't want to shell out $100 for a new one if that's not the issue.

Thanks