Hey guys - I was doing some work under the hood today and noticed something. The unit in the attached picture has a little fan that spins independently of the serpentine belt, but I noticed that it would make a click, start spinning, and then stop. And then it keeps repeating.

I have noticed lately that my heater sucks. Even when the engine is warm, I'm not getting hot air to come out, and since it has been pretty cold up here in the Northwest lately, it's not very much fun in the mornings.

Should that motor be spinning continuously if my heater is on (assuming this is even the heater core)?

Thanks for the help!

 

That, mon ami, is the compressor of the air conditioner.
The operation works via a clutch, that engages and disengages....

The heater core has tubes coming out of the firewall. Two hoses go 'in', one feed and one return. Flushing the heater core (do a search) will likely improve your warm air in the cabin.

 

That is your air conditioning compressor. Not sure on the jeeps, but on my other vehicles, the compressor will come on when you have the front defroster going, to help remove condensation. That's probably what why you keep seeing it engage.


As for your heat, I would think you might have a bad thermostat or bockage in your heater core, which is behind the firewall. You have to dig to be able to see it.

 

Roler is correct, that is your AC compressor. The air conditioner will engage and disengage the serpentine belt based on the demand from your cabin's climate control. Even when heat is selected, using defrost will turn on your air conditioner compressor to dry the air before it hits your foggy windows. It is intermittent only to maintain pressure through the evaporator.


Your heater core is located between your firewall and dash at the passenger's feet. Two hoses enter and exit the firewall from your engine bay to supply your heater core with heated coolant from the engine. They're right next to each other and they pass over or through your spark plug wires on the passenger side of your valve cover. A common cause of heat loss is clogging of the core. Disconnect the two hoses leading into your firewall and flush/backflush to clear your heater core of debris.

 

I wonder if that's the AC Compressor....

 

Yes it is. But the only reason it would cycle in colder weather is if his climate control panel was set to "defrost". It will come on at temperatures 40 degrees and above to help dehumidify the interior.

 

Now, of course, I'm curious, you know that, CCKen. Especially the signature is always....tempting.

Please, do share your 'wondering if'....

EDIT: I think I had to re-read your post a few times lol.

 

Hey, could that be the AC compressor?

Just wondering....

 

Thank you everyone for the very informative posts. Very helpful. It was indeed on the defrost selection, so that explains the intermittent engaging.

I will do some playing around with the heater core to get that heat working again.

Again, thank you. Awesome community!

 

what kind of work are you doing under the hood?