Strange Ticking sound from rear driver side of 2014 LC200 not when running (1 Viewer)

[Gr8Pmkn]

UPDATE - truck started fine this morning. Sound goes away when truck is running. Also, definitely seems to be AC related, when I turned off AC before shutting off engine, there is no more ticking/knocking sound. Maybe a solenoid or switch associated with AC?

Hoping someone can shed some light. Today, we noticed have an odd “ticking" or soft "knocking" sound coming from the rear passenger side of our 2014 LC200 hours after the Cruiser was shut off. It is louder inside the bed area above the wheel well and something we have not noticed before today.

Recording attached - well could not attach, here are some links
Engine off -
Engine running -

Things of note -
The battery was dead today after the vehicle was moved several hours before, not sure if a door was left ajar - we are on vacation and a lot of in and out of vehicle. I will update if it is dead again tomorrow. Hoping it is not drawing too much power.

We had the rear AC compressor replaced last month after it failed.

Thanks in advance,

Lee

 

[bloc]

There is a small pump in the rear of the vehicle that applies light pressure to the fuel tank to check for evap system integrity at certain times when the engine is shut off... could be that.

 

[Gr8Pmkn]

There is a small pump in the rear of the vehicle that applies light pressure to the fuel tank to check for evap system integrity at certain times when the engine is shut off... could be that.

Initially I thought it sounded like a fuel pump. That said, after more tinkering and listening the odd thing is that if I turn off the AC before turning off the truck - doesn’t matter if rear AC had been in use the sound does not recur. That is why I suspect that it is AC related. If AC is left on when shut down the truck gives a final “exhale” of the AC front and rear after shut off and then @ 20 seconds later the sound starts up.

 

[bloc]

Initially I thought it sounded like a fuel pump. That said, after more tinkering and listening the odd thing is that if I turn off the AC before turning off the truck - doesn’t matter if rear AC had been in use the sound does not recur. That is why I suspect that it is AC related. If AC is left on when shut down the truck gives a final “exhale” of the AC front and rear after shut off and then @ 20 seconds later the sound starts up.

Yeah it could be residual pressure in the system balancing. But the evap pump comes up quite often.

 

[Sandroad]

What exactly was replaced during the rear AC work? There is a rear evaporator and rear blower. The only compressor is in the engine compartment. Is the sound on the driver or passenger side? The evap check pump on mine sounds like more of a whirring sound, not a loud ticking. It would take more than a few hours of a door ajar to run down a good battery. I do wonder if the rear AC work, ticking sound, and dead battery are related.