Weird clicking noise behind dash

[4birdman]

OK, I've had this truck for two weeks and it started making this weird noise a week or so after I bought it. It has the rear HVAC and dual zone front.

It is a weird clicking/knock noise under the dash. If I play around with the temp, it will go on and off, sometimes change the way it sounds. It is almost always there though. Driving around it is quiet enough you can't hear it that much, but stopped with the radio off it is pretty annoying.

The HVAC functions as it should, no blend or temp issues.

Any ideas?

 

[rocaloca]

does the sound change with blower speed? you only mentioned temperature.

 

[JochenWoern]

OK, I've had this truck for two weeks and it started making this weird noise a week or so after I bought it. It has the rear HVAC and dual zone front.

It is a weird clicking/knock noise under the dash. If I play around with the temp, it will go on and off, sometimes change the way it sounds. It is almost always there though. Driving around it is quiet enough you can't hear it that much, but stopped with the radio off it is pretty annoying.

The HVAC functions as it should, no blend or temp issues.

Any ideas?

One of your actuators under the dash may be acting up. Wondering however how you state you had no blend or temp issues.

 

[4birdman]

Doesn't increase with fan speed, it is a constant noise.

I was thinking actuator too, but doesn't make sense that I have no issues with the HVAC.