From time to time there is something turning on in my engine compartment. I stood in front of the radiator fans to see if it was that and it wasn't. The sound is very annoying from the inside of the car. It's kind of loud. What is it? is it fixable? I can also see it sucks the electricity up because my lights go dim for a sec when it comes on.I have a 2001 caravan SE 4cyl

 

Need more detail. When does this happen? After you have been driving? Ignition on or off at the time this happens? Does it do it when its just sitting all night? Do you have front and rear AC? Any particulars you might have noticed about when this happens? Does it turn on and off like clockwork? or is there no sequence to it

 

It turns on when the car is on. It sounds like the radiator fan but it not because I checked. I can't pinpoint it. It turns on and off with no warnings when ever it wants. It does it when its cold and hot. does not do it when the car is off. Thanks for the reply

 

It sounds like either a relay or solenoid and i'd look into the starter relay and solenoid combo.Pull the starter fuse and see if it still happens.

 

do you have a/c on the van
in defrost the a/c compressor will turn on/off (cycle) this is to keep the compressor lubed and a/c system curculating
this would also at idle lower the engine's rpm(affecting alternator output)
there may be a problem with the compressor and/or clutch bearings(front of the compressor)or the idle up curcuit
or it could be normal and you just noticed it

 

I'll check the solnoid and i'll pull the starter relay. I'll let you guys know tomorrow whats the deal on the noise.