while driving it switches back and forth continually

It sounds like the ac conditioner programmer has gone out and it needs to be replaced. Here is the air conditioner wiring diagrams so you can do some testing along with the programmer location so you can confirm the problem and the fix.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Confirm that it is getting a good ground, then replace the programmer, try to find a used one.

Please let us know what you find.

Cheers, Ken