Hey guys my name is eric i am new to this site and i have some trouble... :( My truck is a 2003 gmc sierra 2500hd crew cab 4wd
ok so abought 2 months a go my check engine light came on when i was on my way home from work the next day i took it to auto zone . the code read knock sensors so i took it to my mech and he replace them and he also said that comparment was filled with water so he got it out and 2 days later the check engine light was back on . Then abought 3 weeks later he repalce them AGAIN . everything was ok then one day the light was back on then off then on then off it will stay on for aboguht 2 or 3 days then it will just disappear when it feels like it so we checked it again same code knock sensors bank 1 and 2 and i noticed that some times when it comes on that there is a strong smell of like rotten eggs . Then today i notticed that the 2nd setting on my heater and ac dose not work it shuts it off but 1.3.4.5.
seam to work fine
guys i could use the help thanks so much eric....

Ask your mechanic if he changed the knock sensor harness as well. It is highly recommended to change it at the same time. The blower is more than likely the resistor. There is a service bulletin for these. Chevy offers a upgraded resistor and a heavier wiring harness. If you look under the glove box there are some wires running up to the resistor. Pull it out and more than likely it will have burn marks from getting too hot. If so, replace it and the harness. It isn't that expensive from the dealer. I think I spent right at $90 for both. Usually a rotten egg smell is an indication of a catalytic converter going bad. Hope this helps!

well my mech did change the harness for the nock sensors and nothing we also like i said we did them 2 times the sensors . and as for the heat i have not ben able to check it out yet and thanks so much for the help

eric.