reading codes
 

Can someone please explain in ""detail "" how to read and reset codes in a 1991 300 sl , my convertible top will not go down and I need to read an d reset the code to make it go down , I had it checked out a few times and thats the only way the mechanic got it down for me , I know there is something wrong with it , its not going down because the ABS light is on in the dash , I tired cleaning the sensers and I tired a lot of other things , I just havn't figured it out yet , but as of now I just want it to go down , and I need to read and reset the codes , I'm not good at this type of stuff , so I need it explained to me in detail please , and what tool do I need for it , when its done should the car be on and running ?? what position should the key be in , , I already read bobterry's explaination and his forum , i just need it explained a little less mechanical please , Thanks to all

putting the top down ,
 

is there a way to put the top down manully in a 1991 300 sl , if so how ?? is there a do it yourself posted ?? thanks