Rookie needs HELP

I have a 4bay SS car wash that has only wash, wax, spot free rinse and a non functional foaming brush. What do I need to add to offer other services like tire cleaner, triple foam, pre soak?
Can the high pressure and low pressure products be dispensed in the existing wand.
Is a hand held airdryer worth the investment.
Your input is appreciated.

1st priority is getting the foaming brush working. You are missing a big chunk of revenue.

The other functions are less important, but still add revenue at the end of the day. You may apply low pressure functions through the same gun by building a manifold with check valves to prevent high pressure from feeding back into your low pressure lines. Check the water quality of your tap water to see if spot free is warranted in your area. I have no expereicne with the in bay dryer but I would concentrate on the basics, as well as aesthetics around the wash first before I added dryers.

Forget the dryer. All products come out of the HP wand accept FB. You have to get repeat business. How? When they stick money in something comes on, and when they leave their car is clean. Simple huh? You got to get titrations correct. You have been to other car washes, what made you want to come back? Set up TC and Presoak just like foam brush in the equipment room. You can adjust these two so that they come out like a runny liquid. They will cling and not break the bank. ( Your selling air)

I had a similar issue on our Foam Brush and Triple-Shine(Hand-Gun). Come to find out each line(FB&T-S) had a PVC 2"x18"pipe w/ check-valve inline. The PVC had some of that plastic Brillo pad stuff in it. So using Dollar Store purchased colored plastic Brillo, made my foam work. Of course some air/product ratio adjustments were in order. But they worked.
As far as the other product is concerned, I would figure fixing existing issue generally makes know what else to put in easier. Just make sure you have product placement area, plenty of room for pump per product to feed inline to your wand. That just the beginning, Then there is adjusting your pay per service POS. that calls for reprogramming, possible rewiring, new Electric Box/fuses (requires electrician). yeah... lots more....
So Focus on what at hand, then Google Car Wash Suppliers. Then Take lots of Notes.