Can anyone please tell me where l find the dipstick on this, l think it might be under the yellow cap, but its tight and dont wanna force it, another thing could this be why my horn isnt working that it may need oil?

Helen, the yellow cap u refer to is where u pour the oil, the dipstick depending on ur engine is on the right low side or look at the left side, u will see a tube with a plastic ring, that is the dipstick, just pull it all the way out, then clean it wit a rag, put it back again & out, then u will see in the marks if oil is needed, about the horn, the horn is an electrical gadget that does not have to do anything with the lack of oil look in the fuse box to see if there is a fuse blown or maybe a bad connection.