this morning i started my car and drove off. while i was at a light i noticed my idle was fluctuating badly, sometimes dropping to 400 sometimes going to 1000. i also noticed a sound of water dripping. the water dripping sound only occurs whenever i turn on the fan/heat but the poor idle only occurs when i set it to windshield. if i turn it off completely the car idles normal at 750. whats going on?
Could be water dripping on the Fan causing an electrical short causing
large amounts of drain on the alternator causing serious idle issues do to
alternator’s fluxuation in resistance.
that cant be it. the bad idle only occurs when i set the hvac controls to the windshield setting, i can have the fan on and still idle properly. idles fine at all other settings. the water rushing sound occurs when the fan is on.
this seems really weird, im stumped
when u have your fan settings on the windshield, your A/C compressor is turned on, and acts as a de-humidifier, to prevent fog up, which is why your idle goes up slightly when everything is working properly and you have the heat selected on windshield. my idle would fluctuate a little as well, but if i blip thethrottle, everything goes back to normal.
Does your A/C work? I would suggest checking out that unit first, although water dripping on your altenator would mess shit up bad too.
i realize the compressor comes on and that the rpm going up a bit is normal, but trust me, this isnt normal. i have also figured out whats going on. im leaking major fluid when in the defrost position. so that means refrigerant or compressor oil or both. since i was running the car like this im worried that the level is too low and i will fry the compressor. but i need to turn the compressor on and get under the car to find where it is leaking from. any ideas?
What happens of you dont have AC?
- A car that doesnt come with one stock?
- A car that has had its AC removed?
i dont care much if i dont have AC. however my windshield likes to fog up alot in the winter and in rainy conditions and i really need the defrost. do you think there is a way to reroute/rewire so that i can send hit through the windshield without using the condensor?
Uhm yeah … take off your AC 
Seriously though, if it’s leaking refrigerant … that stuff is not good for you, or anyone else. And I think you can get a nasty environmental ticket for doing it. I’m sure playing dumb will get around that.
Is there an AC fuse? Pulling that will kill the compressor. If there isn’t, you can always just unplug the signal wire going to the AC unit.