I have 99 Silverado that at time sounds like a relay is cycling in the dash behind the heatrer controls. It happens when the truck is running and when turned off. I can be standing outside and here this ticking sound. Does any one have any ides before I tear apart he dash looking for the source?

 

i have the same problem in my 04.....not really sure some of the mechanics have told me its something bout the heater core...but im not sure 100%

trevor

 

I had the same problem in my 04 and 05. I fixed it buy getting an 03 2500 HD. No more clicking sound. I don't think that was the help you wanted.

 

Anyone else???

 

i had an issue with a relay firing and it was near where you describe. it was my courtesy lights relay. the lights would go insane. as i drove it would flash like strobes randomly. and it was traced to a not sooo good fuse. new fuse and no problems. i dont know. check some fuses. if anything is acting up look toward the fuses and some other connections where it doesnt require a tear down of the dash. because thats hell.