I have a 2001 Mustang GT with about 35k on the clock. The other day, I was cruising down the interstate with the AC on and every 10-15 seconds or so, I would feel a little jerk or hesitation with a tick sound. I turned the AC off and it stopped. I put it on just defrost and then defrost/floor and it did it again. It doesn't do it with regular vent and just floor. The AC blows really cold still. What could be causing this?

On a side note, the light that makes the AC/Heat controls glow is out. Is there an easy way to replace that? Could it just be a fuse or would something else not be working if it was a fuse?

Thanks!

 

It's typical for your ac/heater to cycle like that and make a tick or thunk.

There is a TSB on excessively loud/frequent 'thunks' from your ac/heater

 

So is that something I should make the dealer fix or can I do it myself? I found the TSB but I can't find any details.