I had been talking with a good friend (Alan) on the local ham radio repeater and he mentioned that I needed to stop by and check out some of his new "stuff" that he had added to his tool bench. Alan had gotten some new equipment to do A/C work on the current R-134a systems like I have in the TJ. That sounded like a great opportunity to try out the new equipment and check the performance of my A/C system at the same time. My TJ has been on the road for just under 8 years now and although the vents still blow cold air, I can tell it's not as cold as it once was.
Since my A/C was blowing cool air, I expected no major problems with the system. If I had a significant leak of any kind, there would be no cool air at all as the refrigerant would have leaked out. When that happens, the low pressure cut-off switch prevents the compressor clutch from engaging.
The first part of the tune-up was getting the equipment attached to the TJ. That meant attaching the two hoses (high and low) of the A/C pressure gauges to the service ports on the TJ's air conditioning system. The gauges are used to measure the high and low pressures in the system. Tables in the factory service manual indicate the operating pressures for properly charged system.
The low pressure port, shown above, is located between the dip stick and the battery on the a/c low pressure line.
I unscrewed the cap from the service port and snapped on the low pressure coupler to the port. It is a quick disconnect coupler that simply snaps onto the low pressure port. The low and high pressure ports are different sizes to make it simple to get the correct hose attached to the right port.
After finishing with the low pressure port, I attached the high pressure hose to the high pressure service port. This port is located right at the the compressor on my TJ. It too has a screw off cap that I removed before the high pressure hose was connected.
The remaining hose that is attached to the gauge manifold is connected to the refrigerant container. Alan had a partially used can, about 3 ~ 4 ounces remaining, already attached to the hose so I set the can in a safe place to keep it out of the way. The valve on top of the can will be opened if we determine the system is low on refrigerant.
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