Cadillac Repair: What does a hall effect switch..., brain tumor, hall effect switch

Question
What does a hall effect switch do?  I am having problems with my 94 DeVille.  It is surging and it dies when I get on it going up hill or starting out from a light. The service engine light is on.  It has 105000 miles.  I am on a fixed income.  I have a brain tumor.  They won't let me work any more, so I can't put alot of money into this car. Please help me.  

Answer
Hi John, The hall effect switch lets the computor know the position of the camshaft or more specifically the #1 cylinder is. There are alot of things that could cause your problem and knowing the code that turned on the check engine light would help with the repair. With the engine running push off and warmer on the cliamate control panel for 5 seconds or until it goes into diagnostics. Then write down all the E_ _ codes and all the EE_ _ codes and let me know what they are so I can further advise.  To exit diagnostics turn the key off and the next time the key is turned on the dash will be back to normal. Bill