loud "click" behind dash board 97 blazer

[berniescout]

most days after driving a mile or so a loud click is heard from behind the center dash board in the area of the radio. i think it is heat related. 97 blazer automatic. anyone else hear it and what is it???

[BlazerLT]

Yes! I have heard it too!

Metallic SNAP

Don't know what causes it.

[bpletcj]

Yes I do as well, has the same sound as when you push in your cigerette lighter and once it gets hot it pops out.

[BlazerLT]

From what I have heard it is the dash expanding with heat.

The sound never happens during the summer.

[barpat96]

What a relief! I thought i was going crazy

[chcknugget]

I think it's actually the windhsield that makes the noise on my vehicle. Especially if you set the defroster on high heat. It sounds like magnetic popcorn! (hahaha sorta)

[BlazerLT]

glass will not make that noise.

[chcknugget]

I must have a different noise. On my car it definetely comes from the glass when the heat is on. It might be the inside layer expanding from the heat while the outside layer is still exposed to cold. But it's not just a click, it's more like a high pitched: PUNK!

[wolfox]

That metallic "ka-PING" usually happens when the blower is set for heat, whether I am defrosting glass or warming the boots in winter too. It drives a buddy of mine crazy, thinking that every odd noise in a vehicle is a problem. I figured it was either a blending door or a relay clicking over when you have gotten to max heat and the engine totally warmed up. It will not do this in warmer weather, and the funny part is - when the engine reaches operating temperatures with the heat on is the only time you hear it. Seriously, temp rises to 190~200 with the blower up and on heat - *ka-PING* it's done! Carve that turkey up baby.

[BlazerLT]

Yea, and it will happen from time to time with no real cause.

Kaping! two hours go by.....KAPING!

[berniescout]

good way to describe it KA-PING "sounds" like it is normal, but what is it? definately not the glass. if it were it would crack the glass. I go with the expansion from heat of something in the dash behind the radio.

[Allbert]

My '96 S-10 used to make something like an occasional tick noise with the defrost + heat on. I always figured it was something expanding against something else due to the heat too.

[BlazerLT]

Yip, that is what it is.

Heat expansion.