if (wheelRevTime >0 && <10 && Location == "Start" && Speed == "Stop");{
There are a number of things wrong with this line.
First the semicolon means that whatever is in brackets is unconditionally executed so the "if" does nothing useful.
Second, this doesn't do what you appear to think it does:
wheelRevTime >0 && <10
You have to repeat the subject of the test, eg.
wheelRevTime > 0 && wheelRevTime < 10
Third, I wouldn't be using the String class myself. Use a variable with values like 1 = start and 2 = stop. Otherwise you might get memory fragmentation.
set pin HIGH
This is just pseudocode, right? Better look up the digitalWrite function in the reference section.