Clicking noise behind dash when A/C is on?

[techno]

My air conditioning has stopped blowing cold and I now have a repetitive clicking noise from behind the dash when the a/c is on. It clicks every 5 seconds or so. It only happens with the a/c on. Fan speed, temp and fresh air/recirc does not effect it.

I had the system re-gassed last week and it worked fine on the way home from the shop, but now my brother is driving it from Pittsburgh PA to San Antonio TX and he just called me from Cincinnati to report this problem, so I can't take it back to the shop.

My searching the forum is pointing me toward one of the servo motors as a possibility. Does anyone have experience with this or something similar?

 

[BoomSticks]

I also have clicking behind the dash of my 99 Limited (auto climate control) when the AC is running.

Everything seems to be working as it should. AC blows cold, heat blows hot, and the clicking is only when the AC is on.

My guess is that the clicking is a relay when the cabin temperature reaches a certain point and the auto climate control is telling *something* back there to turn on or off.

Maybe it's the relay that controls the motor for the mixer door?

 

[techno]

That's interesting and I was initially think of something similar, however I do not have the auto climate control. I'll check my FSM for any other relevant relays.

I'm going to ask my brother to check the blend control motor next time he stops for a rest, just to rule that out.

 

[Weagle2]

Mine was mixer door. $150 repair.

 

[techno]

Took it to an a/c specialist this morning. They couldn't find anything broken or malfunctioning, however they did find that the system was over pressurized significantly, causing it to 'short cycle'. The clicking sound was it recognizing the high pressure and turning off, then restarting shortly after to try again.
The first shop had charged it 2.5 lbs, when it should be at 1.5. It's working normally now.

 

[1999LTD]

I have a clicking behind my dash but it's stops when I have the temp turned ALL the way down. Different vents work but no heat. Blend door or something? Any ideas would help. I have a recording of it.