ronnied214

Hey guys,

I have a 2014 IS 250 and I recently had a new battery installed and after the installation the car vibrates when I turn on the defroster regardless of the speed but it doesn't vibrate if the direction is aimed at the people or the feet in the car.

f I set the defroster to Cold air or Hot air it vibrates, if it is set to 1 speed or 5 speed it vibrates.

The only setting that seems to matter with the air blowing towards the front windshield. Any Idea what caused it? BTW I do not trust the mechanic that installed the new battery, it took him almost 2 hours to do so, therefore I am convinced they intentionally or accidentally screwed up else where.

swaangin

My RPMs go up when defroster is on.. I think it's normal.. which car model do you have?

Sasnuke

When you turn the HVAC to Defrost or Foot/Defrost it engages the A/C compressor in order to clear the fog inside the glass...I'm assuming this is why you turned it to Defrost...this places additional load on the engine which can lower the RPM at idle.
Since the battery was replaced this likely reset the ECM's learned value of the base idle of the vehicle...which is based on having a clean throttle body with no carbon buildup around the flap.
I would suggest cleaning the throttle body and see if that corrects the issue. Also, when was the last time you cleaned the throttle body? If it's been more than 30K miles, then it's going to be dirty for sure.

ronnied214

It's a 2014 IS 250 normal edition. This problem didn't happen the last time the battery was changed so this is why I have been worried.

Thanks for your reply

ronnied214

Thanks for your input. I just completed the 60,000 mile "tune-up" or whatever it is called that was recommended by the dealer and they said everything was great and the battery died 3 weeks later so I do not trust them at all. The vibration occurs both at rest and when driving but only when the heat/ac is set to defrost the front windshield it never occurs when it is blowing at my feet or at me directly.

I will checkout the throttle body and be sure to clean it, thanks for your suggestion. I assume the throttle body was supposed to be cleaned by the dealer but I'll check it out.

Sasnuke

Usually a throttle body service is extra on top of any maintenance schedule stops, so if it was recommended, then it wasn't likely done unless you authorized it.
Although the maintenance program at your dealer may differ from the ones around me, but I'd confidently say it's not done as part of a prescribed service, but rather an add-on service...like an alignment or efi flush.
If it wasn't cleaned then I'm sure that's what is causing your idle/vibration issue. It's not an uncommon thing to happen, so I wouldn't worry...it's just a sign the throttle body is dirty and does need cleaning.

ronnied214

Thanks Sasnuke,

I appreciate it a lot!

ronnied214

Hey Sasnuke,

So today it started making a rattling noise when the heater or AC is on and this noise is coming from the center vent. The noise occurs regardless if it is on defrost or if it is pointing at me. The vibration still occurs when the defroster is set and whether the car is idle or moving. Curious if you might know what is causing this?

Sasnuke

Without hearing it I couldn't even guess what the rattling could be.
If it's occurring when the Defrost is not set, then it's likely not related...but that's just a guess.
The assumption is the vibration is being caused by a low idle when the Defrost (A/C) is on...so I think tackling one issue at a time is the way to go.
Clean the throttle body first and then see what issues still remain.