I have a 1998 F-150, and everytime I turned the AC on, I can hear and see the clutch engaging for a couple of seconds and then it disengages. It does this same thing over and over as long as the AC is on. I tried to add a can of freon R134A, but the system wouldn't even take it. Does this means that I need to replace the compressor? or what do you recommend?
An expert who has achieved level 3 by getting 1000 points
An expert who has finished #1 on the weekly Top 10 Fixya Experts Leaderboard.
An expert that got 20 achievements.
An expert that got 10 achievements.
Re: AC clutch engages and disengages constantly
The system is low on charge, as far as the attempt to add refrigerant u did something wrong, no sure what, the rapid cycling of the compressor is only caused by a low charge 99% of the time. Have u hooked up a set of gauges to check pressures?
a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need. goodluck!
- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
If all you get is hot air there are several possibilities. The compressor is driven by the serpentine belt and is engaged and disengaged by an electric clutch mounted on the compressor drive pulley. With the engine running, have an assistant turn on the AC while you observe the AC compressor clutch. If the clutch engages, you can be reasonably sure that the system has freon, and the electric circuit is OK. If the clutch doesn't engage, which is the most likely situation, either you are low on freon, the AC clutch relay is inop, or AC compressor fuse is open (blown). A search of Google images will give you the location of the AC relay. You can pull out the relay, carefully remove the cover, reinsert the relay, and engage the compressor clutch by manually closing the relay contacts. Warning: do this only for a second or two in order to see the clutch engage. If the clutch does engage, then you are probably low on freon. There is a safety switch that prevents the clutch from operating if there is not enough freon in the system. Hopefully, this is the case. Go to Walmart and get two cans of r-134 and the inexpensive kit, and following their instructions, charge your system. If this is not the problem, you'll need a set of AC gauges and the skill to use them. Hope this helps. Dano
This won't be a complete solution, but here's a place to start. Have the engine running, truck in park. Open the hood and stand to the side of the truck. Have someone help by sitting in the truck turning the AC on and off over and over. Your AC pump runs off your engine belt and has a clutch on it so that when you aren't using the AC, the pump doesn't turn. You should hear the AC Clutch engaging and disengaging as your helper cycles the system on and off. If you don't hear this, it's probably an electrical problem and the clutch isn't hearing the signal to engage. If you hear the clutch clicking on and off (usually a pretty discernible click) and if indeed the system is charged well with refrigerant, then I would suspect the clutch may be worn to the point that it won't engage. Either of these is a fairly expensive fix, and should probably be done by a mechanic. My truck has to be drained of refrigerant before the clutch can be changed, and if this is the case for you then that refrigerant should be captured and recycled rather than let go into the atmosphere. Also, if work needs to go this deep, filters should be cleaned and lubrication replaced as well... a mechanic will do a great job here. If it's electrical then the solution shouldn't be as involved, but nobody likes electrical work so the price is usually high anyway. :) Good luck!
Did you check the AC relay? Usually located under the hood, try swapping it with another relay with the same part number that isn't required to run the vehicle. If the AC now works, then replace the relay. If not , then verify compressor operation. With the engine running, watch the compressor clutch while someone else turns on the AC control. The clutch should engage and begin to run. If not, then find the pressure cycling switch usually located on the accumulator. Disconnect the harness and jumper the contacts. With the engine off and the key turned on , turn the AC control on. You should now be able to watch the clutch engage and disengage by removing and replacing the jumper lead. If it does, then replace the switch. I hope this information is helpful. Thanks for trying Fixya.
first turn the ac off and then start the engine. you may want to lift the hood so you can hear the next step better. turn on the ac and within a couple seconds not more than 5 or so you should hear a click sound. This is the ac clutch engaging. if you don't hear a click you can double check the compressor has engaged by looking to see that the center of the ac compressor is turning with the outer pulley. if it is not most likely you don't have enough refrigerant in the system. i would suggest getting an ac pressure tester they are fairly inexpensive but this will tell you for certain if you have enough refrigerant or not.
it could be the air conditioning clutch going out. to check turn your car on and idle it with ac on and hood open. at the ac compressor it will have a pulley on it with a clutch that engages when the air conditioning is on. if it engages and disengages it can be the clutch itself has gone bad, the ac clutch will also disengage if there is not enough freon in the ac system, will also engage and disengage if the pressure gets too high in the ac system. Depending on the year of the vehicle it will disengage at full throttle and come back on when you are not at full throttle.
If it is a metallic sounding screech for example take a coke can and drag it across pavement kind of sound it could be a bad compressor or a bad ac clutch. If it is a more rubbery sound for example a car spinning its tires kind of noise it could be a loose belt.
1. Check to make sure all belts are tight under hood
2. start car and look at ac compressor to make sure compressor pulley is turning and that the fan clutch is engaged spinning