I am looking to see if anyone can help me figure something out about my a/c system in my 2006 Honda Element. The wife was saying she was just driving along and the a/c just quit...no noise nothing just quit blowing cold and she took note that the compressor was not engaging when this happened. I have looked this thing over with out totally cutting open wire looms and chasing wires but I have followed the piping paths and the wiring paths and did some meter reading around and this is what I've come up with. The compressor turns smoothly by hand.....the field coil is showing 4 ohms......but I am getting no power at the compressor.....I have gotten into the relay box and located the condenser fan and compressor relays and have swapped them...the fan still runs.....i have disconnected the dual pressure switch and jumpered it and the condenser fan comes on but the compressor does not engage......with the pressure switch plugged in i get the same result with the fan coming on but the compressor will not engage......the pressure switch is reading closed......am I missing something here? I am not seeing any other electrical components here so why would one suppose I'm not getting power to the clutch at the compressor???? I did just have the system serviced about a week or so ago but I think this whole deal is just coincidence. When we serviced the system we pulled it down and held it under a vacuum for about ten minutes or which revealed no leaks but I have done this before and later found out that the schrader valve was the culprit because the leak test went good then as well....I am at the end of the street here in doing what I can do without getting some gages on it to see whats happening internally to the system which I wont be able to do until Tuesday or Wednesday....I appreciate any help......thank you
Edited: Sun June 10, 2012 at 10:29 PM by stumble
You need to check if there is even refrigerant in the system.
.....so i took it over to my shop and we sucked out the gas and found the system was fully charged.....went with the idea of hot wiring the compressor, because the field coil was only reading 4.3 ohms and from what I could find on the internet it seemed like 4-5 ohms is what that should be at....anyway the compressor worked....under a vacuum the pressure switch read open and filled with .55 Kg of freon in the system it read closed.....but for some reason I was still not getting power to the compressor.....was getting 13.5 volts at the connector to the pressure switch.....and through all of this the green a/c light on the dash was on.......rang out the comressor relay in the engine compartment relay box and it seemed solid.....could not put two and two together without having a schematic or a logic breakdown for the system.....started pulling fuses out one by one and checking them.....having already swapped relays in the engine compartment relay box we ruled that out.....so one by one we went and sure enough we found that the 30A condenser fan fuse in the engine compartment relay box. not the relay but the fuse, was popped......dropped in a 20 amp fuse because that's what I had in my hand at the moment and wallah....to life she came......turned it all off and replaced the 20A with a 30A and let it run for about 15 - 20 minutes and she held up.....drove her home about 15 miles and she was still cooling when I pulled into the driveway.....go figure.....I will drive it for the next couple of days and see how it holds up.....the million dollar question.....why did that fuse blow? the day this happened it was about 105 F in southern Arizona and I know that heat can raise the resistance of metal but I don't think there was so much heat that it couldn't have overcome that little bit of added resistance due to the heat.....not sure....thoughts????
I forgot to mention.....when we pulled the vacuum we did a leak test on the system and it leak checked good....we did change the high side schrader valve in the service port.....one interesting thing that I might add, at least I found it interesting, is when we serviced it last Tuesday we pulled down the system and recovered about 1/4 oz. of oil and today when we pulled the system down we recovered about 1 1/2 oz......not sure if this is because the system was sitting idle for a few days while I drove with no a/c....not sure about this one either.......
A fuse will blow for one of two reasons: current exceeded it's capacity, or the fuse was defective or damaged. The simplest possible explanation is that you had a momentary short circuit in some frayed wiring that you have subsequently interrupted either through road vibration or your explorations.
The rating of the fuse does deteriorate with heat, but it takes a fair bit of heat. At the boiling point of water, your 30A fuse would be de-rated to 24A. The heat would be from all sources: so if you combine the ambient temperature with the engine compartment heat and add a bit of corrosion you might get to those levels. Of course, you would also be melting the plastic housing around the fuse.
The other thing is that the rating of the fuse is a bit misleading -- there is also a time element The fan will draw 20 to 30 times it's rated current as it starts and builds up speed. So if the fan normally draws, say, 5 amps, it could have a momentary inrush current of 150 amps. The engineers know all about this so they add a device called a thermistor to help control the inrush current. The current may still exceed the fuse's stated rating, but the duration is so short the fuse can handle the excess. Thermistors can fail in one of three ways: open circuit (like a blown fuse), closed circuit (ie: they are now a simple wire path) or parameter change (ie: they still kind of work, but the amount they control the current has changed). Open failure is the most common (>60%), followed by parameter change (>20%). So you have perhaps a 30-40% chance of the fan still appearing to work even with a failed/failing thermistor, at which point you are rolling the dice as to whether the fuse will blow before the fan gets up to speed. The only way to verify this short of taking apart the fan to get at the thermistor is with laboratory grade test equipment -- it all happens so fast you need a scope to capture it.
Or it could just have been a bad fuse. Poor quality control, a few years of vibration, and then a really hot day when it was being taxed to it's limit: POOF! Personally, I'm an Ockham's Razor kind of guy: Keep a spare 30A in the glovebox and show the wife where the fuses are. Worry about it if it happens again.
I've saved hundreds on service by spending thousands on tools.
well I went out this morning to go to work and fired up the car and the compressor would not turn on....got under the hood and found that 30A condenser fan fuse popped again.....now I'm really stumped because I'm not sure if it is my condensor fan that is causing the problem or could it be thta the compressor is drawing too much current when it kicks on and is popping the fuse.....I am not even sure as to how to go about isolating which component could be the culprit......thoughts??????
We've updated our forums!
Click here to visit the new forum
Copyright © 2016 Arizona Mobile Air Inc.