So I have noticed a vibration in the steering wheel of my 2003 accord 4cyl when I am parked or at a red light. The vibration cycles on and off. I checked under the hood the other day and the cycling appears to coincide with the radiator fan kicking on and off. This vibration is more pronounced when the vehicle is in Drive, versus Park. The RPM's remain steady around 600 throughout the whole process.

I am confused why the engine is "struggling"; especially with the fans being electric and the fact that alternators don’t have a clutch like AC compressors? I assume that an increased load on the engine is the cause of the vibration in the steering wheel? This doesn't make complete sense because I would think the RPMs would dip at the same time the fans kicked on if it indeed was the increased engine load that was responsible for the vibration.

The car drives fine otherwise and never appears to be at risk of stalling, just a bit unnerving. Currently I have 80k on the vehicle. Any ideas on a remedy?

Thanks!

 

You already identified your culprit. Your cooling fan cycle on and off at the same time your ac compressor cycles on and off. If your car is in either defrost setting on the HVAC contoller it will run the ac from time to time. It is not at all uncommon for a little vibration at idle when the ac is running.

 

My 2003 stated vibrating at a stop when the AC compressor started seizing up. The compressor kicks on when in both defrost modes and so do the fans

 

In 2003 (unlike earlier years) the AC engages with the defrost settings WITHOUT the green lamp on the AC button. And you can't turn it off. Only way to turn it off is direct the air elsewhere other than the windshield.