Easykill had the same problem on Saturday - turned out to be the vacuum pipe to the manifold was disconnected. Check the pipes as they could have a leak. Also put your finger on the solenoids and get someone to switch to 4H and 4L if they are working you will feel the “click” - engine must be running.
The solenoids are located on the driver side of the engine bay half way to the front – if you can’t locate them I will get Easykill to take a photo and post tomorrow morning (he is working late shift this week)