Clicking and low voltage

[floatingpig]

Hi guys,
I believe I had a previous post regarding this and I need a little help figuring out what is going on. Since I bought my Explorer, I have had an issue with the air conditioning compressor cycling on and off. With the clicking on and off, it would put a load on the engine and dramatically lowering the voltage to the point where the revs drop way down and the engine almost stalls (it did stall once), along with all of the lights dimming and the voltage gauge dropping. One day while on a road trip the alternator finally gave out. I got towed to an AutoZone where I swapped the alternator with their highest end model and installed a new battery (also highest end, Duralast Gold). The issue (which I always thought was related to the alternator and battery) was gone! Until now... I replaced the alternator in October 2013 at 148k miles. I now have 151k miles and the clicking and voltage problem has started up again, just like last time.
It is probably nothing, but I am very frustrated as I don't think it is supposed to happen, and it didn't happen for quite sometime. What should I replace next? Any ideas? :roll:

Thanks guys!! And sorry for the wall of text (I like typing).

 

[DjDom]

Hmm, what engine is it?
How the clutch for the AC works is it's an electromagnet that pulls the clutch to activate the pulley.
Sounds to me like that magnet is acting up..
I'm not sure where the plug is, but try disconnecting the wire that goes to that magnet and see if it continues..

 

[floatingpig]

Hi DjDom,
I have the 4.0 SOHC. Any photo that I can use as a reference for what I should disconnect or part number if I determine that I need to replace it?
Thanks for your help!

 

[bobflood]

Don't know about the 4.0, but on my 5.0 the plug for the AC compressor is right on top of the compressor just behind the pulley/clutch assembly. Good luck.

 

[floatingpig]

I just thought of this and think it may be relevant. It only does this when the car is idling in park or neutral. If I'm in reverse or drive, it seems to run fine. I went to AutoZone and they tested the voltage. The alternator charges at 14v with the air conditioning off. When the AC is on, it is also 14v, but the click drops it way down to 12v, almost killing the engine.

 

[my98nnj]

The compressor will run on any setting except floor or vent. The purpose for that is to dehumidify the incoming air to keep the windows clear.

Your issue isn't voltage related, but rather a load on the engine that isn't being compensated by the Idle Air Control Valve. (IAC)

What's happening to you is that the load on the engine is bringing down the engine RPM's which in turn is effecting the alternator output and also giving you the stall now and then.

You need to figure out whether or not the IACV is working as it should. It should be adjusting the engine RPM's to maintain the correct idle speed when the compressor cycles on and off. Seems this isn't happening and is what's causing your issues.

 

[bill06447]

The compressor will run on any setting except floor or vent. The purpose for that is to dehumidify the incoming air to keep the windows clear.

It even (supposed to) work in the "floor" setting, any time the temp is above 50. According to that trusty, dusty old zippered book thing in the glove box no one ever looks at, called an "owners manual"

Bill

 

[floatingpig]

The compressor will run on any setting except floor or vent. The purpose for that is to dehumidify the incoming air to keep the windows clear.

Your issue isn't voltage related, but rather a load on the engine that isn't being compensated by the Idle Air Control Valve. (IAC)

What's happening to you is that the load on the engine is bringing down the engine RPM's which in turn is effecting the alternator output and also giving you the stall now and then.

You need to figure out whether or not the IACV is working as it should. It should be adjusting the engine RPM's to maintain the correct idle speed when the compressor cycles on and off. Seems this isn't happening and is what's causing your issues.

I'm on a flight to visit my brother right now so I will play with the Explorer when I get home...wish I could have driven it! My Explorer is one of the best riding cars for long trips. My dad's $60k VW Touareg is great too, but my Explorer doesn't cost $400 to replace a headlight bulb.

Anyway, back to the issue. Is there a DIY someone could link me on finding the IACV and how to test it? Would like to do some reading up on this during the flight to kill time.

 

[floatingpig]

Hi guys,
Just back from Wisconsin (COLD!!). I took a look under the hood and couldn't seem to find the IACV...I know what it is supposed to look like, but couldn't find it on the engine. I will take a closer look tomorrow if someone can help point me to the right spot. Is there a way I can clean the current one to test it?
On a related note, I noticed something I hadn't noticed before. Right before the AC Compressor clicks on, there is another click that sounds like it is coming from a fuse box under the air intake filter. Could it be a bad connection on a relay perhaps?

 

[floatingpig]

The compressor will run on any setting except floor or vent. The purpose for that is to dehumidify the incoming air to keep the windows clear.

Your issue isn't voltage related, but rather a load on the engine that isn't being compensated by the Idle Air Control Valve. (IAC)

What's happening to you is that the load on the engine is bringing down the engine RPM's which in turn is effecting the alternator output and also giving you the stall now and then.

You need to figure out whether or not the IACV is working as it should. It should be adjusting the engine RPM's to maintain the correct idle speed when the compressor cycles on and off. Seems this isn't happening and is what's causing your issues.

I cleaned the IACV today with some brake cleaner. I got a lot of gunk out of it and it looked a lot nicer when I put it back on. However the issue is still occurring. Is there a way that I can further test the IACVs function?

 

[bill06447]

Might have an AC system problem, compressor kicks on, too much of a load so it kicks off, the cycle continues. Check your system pressures? Compressor/clutch condition?

Bill

 

[koda2000]

Might have an AC system problem, compressor kicks on, too much of a load so it kicks off, the cycle continues. Check your system pressures? Compressor/clutch condition?

Bill

the A/C compressor should not be coming on in the VENT position.

 

[floatingpig]

the A/C compressor should not be coming on in the VENT position.

I don't use the Vent position. I either have it in A/C or defrost. The air conditioning always works great, very cold, even though the compressor cycles on and off.

 

[bill06447]

Sounds like the compressor is putting an unusual amount of drag on the engine. Possibly overcharged system, or faulty compressor, my buddy had this problem in his 88 GMC until the compressor finally seized up.

Bill