My A/C compressor clicks on every 6-7 seconds

connorek

New Member
Original poster
Joined
Jun 24, 2021
Messages
12
Location
Austin Texas
Hey everyone. I’m a long-time reader, but just made an account to make this post. I have a 98 4.0, and haven’t ever had any issues. Recently, my dad and I replaced the water pump, and coolant housing, after we put the wrong fluid in the radiator and had to flush out the entire system, compromising the water pump. After about a week after that, I realized my AC compressor would click on and off and sometimes and my AC wasn’t cold anymore, except for random occasions when it would turn on and blow cold instead of hot. Our first conclusion was that it needed new Freon, but the system was already filled. We looked under the hood and recognized that the AC compressor would spin for three seconds, and then stop for about 6 to 7 seconds and this would cycle for as long as air was blowing in the cabin through the vents, or the dial was set to the AC being on. We already replaced the AC fuse, and it still keeps happening. I’m relatively new to TJ‘s but still have a good amount of knowledge about cooling systems. But I’m just stumped. I’ve seen a few threads on here talking about the same problem, but never to where it’s blowing hot and not cold through the vents. I’ve attached a video to this post to reference, and I wanted to ask if anybody has seen anything like this. Thanks so much.
 
I'd have a leak test done by a competent a/c shop. You might have bent/cracked a fitting so it's no longer fully loaded with coolant.
 
How do you know the Freon was filled?

Mine cycled on and off as you say. Wasn’t as cold as it should be. Spent $40 at Oreilly’s on a refill kit and topped it off. All good now.
 
How do you know the Freon was filled?

Mine cycled on and off as you say. Wasn’t as cold as it should be. Spent $40 at Oreilly’s on a refill kit and topped it off. All good now.
Whenever we were filling up the Freon, the gauges we used for it said it was already full.
 
I'd have a leak test done by a competent a/c shop. You might have bent/cracked a fitting so it's no longer fully loaded with coolant.
The cooling system and coolant are perfect, realistically it’s just that my AC isn’t blowing cold in the hot Texas summer that concerns me.
 
The store bought refrigerant in a can with one hose and gauge doesn't tell you enough information as to how the system is operating. You need to have a competent friend or shop connect a gauge manifold to see what the suction (low pressure) and discharge (high pressure) sides of the system are doing and check system temperatures. Possibly sniff or add dye to the system to check the compressor, condenser, O rings, pressure switches and lines for leaks.
 
When I bought mine, the AC wasn't functioning properly.
System was low checked with a manifold dual gauge. The cap was missing on the low side charge port. When I took the cap off the high side...there was a leak. Replaced the Schrader valve. Then recharged. Limped it through the first summer but it wouldn't cool properly.
Next spring, replaced the accumulator, evacuated the system, recharged by weight 1.25# . It cooled but "short cycled" turned out it needed a low pressure switch. $14 later and its been excellent for 2 years now.

Sensitive to charge level. Best way is weight.
Low refrigerant should freeze your evaporator. High refrigerant would make it warmer.

If the system has been empty or open at ALL, do yourself a favor and replace the accumulator, vacuum down, recharge by weight.

Did I mention recharge by weight?
 
it sounds to me like you have a bad high pressure switch....find your pressure switch , unplug it and put a jumper wire in the connector and try turning it on. if it does it with the high jumpered try the low pressure side....
 
OK, I just got A different AC pro can with a gauge, and as the Compressor would kick on and off, the pressure would go a little past the recommended fill level, and then kick back down as the compressor turned on. I’m just completely stunned on why it would even do that, do any of you have any experience with that happening or why it would happen?
 
OK, I just got A different AC pro can with a gauge, and as the Compressor would kick on and off, the pressure would go a little past the recommended fill level, and then kick back down as the compressor turned on. I’m just completely stunned on why it would even do that, do any of you have any experience with that happening or why it would happen?
Because your AC system has two halves - the high side & low side. When the compressor is off the two sides will equalize in pressure. When the compressor turns on the low side pressure drops & the high side pressure climbs.
 
  • Like
Reactions: reddvltj
OK, I just got A different AC pro can with a gauge, and as the Compressor would kick on and off, the pressure would go a little past the recommended fill level, and then kick back down as the compressor turned on. I’m just completely stunned on why it would even do that, do any of you have any experience with that happening or why it would happen?
Add some freon and it’ll stop moving