1963Peterbuilt

Newby here. I've been working on a '99 XJ that my son and I bought. Sorry if this has been covered, I used the search but couldn't find anything related to my issue. If I have the air temp setting on the last 2 or 3 coldest setting, there is a loud clicking noise on the passenger side floor. Bump it up a couple clicks and it goes away. Doesn't matter if the AC is on or not. Thanks!

Saudade

Your blend door is electric and uses a servo motor to move it around. I would check the blend door and actuator. It's under the glove box.

Bradner

I know this is a year late, but did you ever find the source of the noise? I just replaced my heater core along with the blend door actuator and now I am hearing a clicking sound coming from the blower motor when the temp is set to cool and only when the temp is on cool. It definitely sounds like the squirrel cage is hitting something. The only thing I can think of is the door immediately aft of the blower motor. I’ve read that the blower housing can be adjusted slightly to center it in the heater box opening. I really hope I don’t have to remove the heater box again. I just put the dash back together!