My AC pressure switch under the battery tray is leaking, as pictured. I want to fix this before it has a chance to cause me grief through my AC leaking down and stopping in the summer or oil starvation of the compressor causing a nightmare scenario. Do any of you folks have pictures of this switch on its own and the following information?

• Is it the Schrader valve or threaded fitting type switch?
• What size o-ring does it take assuming it has one?
• What's the part number of the switch? Or is it time for me to hit the used market?
• What size wrench fits it? (When I briefly inspected it I was unable to get access to it with my calipers or adjustable wrench to check and want to just get a crow's foot to get at it)

I searched the forum, the PDF parts diagrams/service manuals I have, and the parts listings on mazdausa and couldn't find this thing anywhere. It's visible on the parts diagrams as part of the pipe 61-466 but has no number of its own. I want to find out if the switch itself is leaking or its fitting but I'm not even sure what type of switch it is. Generally there are two types; one screws onto a Schrader valve and can be removed or replaced without evacuating the system, the other type is just threaded on and the system must be evacuated to remove it which sucks. Both usually have an O-ring which can be the culprit for the leak or if you're unlucky the body of the switch can leak too.

Thanks in advance.


Parts diagram



Leaking FD AC pressure switch

 

I THINK it's an O-ring on the switch but not totally sure. It's not a common leak I don't believe.

Dale

 

There is an o-ring under it. The pressure switch is a sealed unit

 

Here’s everything you should need, the sensor is a 21mm btw.

 

Crap, I will have to evacuate the AC system to fix this since it isn't the Schrader valve type fitting. Thank you @CREEPENJEEPEN it looks like I'm either going to need two crows feet for this to counterhold the cube the sensor screws into, or will have to pull the battery tray.

 

I decided to finally evacuate and take the system apart and I wanted to provide an update on this because I found a solution. Luckily, there is an off-the-shelf replacement for this switch that is reasonably priced and readily available, the PN is SW4086C, made by UAC. Creepenjeepen's measurements gave me a hunch that this isn't a metric thread and sure enough it's 3/8" - 24, so thanks again for posting those. This UAC switch is a binary switch for R134a systems and is labeled with with a low off pressure of 2kg/cm^2 and a high off pressure of 32kg/cm^2, assuming the units are the same in the above picture of the OE switch, that's pretty close to the OE split of 2 and 27, and it makes sense that the high pressure cutoff would be a bit higher because R134a systems have higher condenser pressures than R12. All you have to do is clip the pigtail off of your broken or leaky stock switch and crimp some female spade terminals onto it so you can hook it up to this switch. It's just a shame MANA didn't use a common drier or even common drier fitting sizes or a female switch that fits a Schrader valve fitting. I'm really curious how the economics of using a bespoke drier that has no cross reference application instead of the common part the Denso systems use made sense when they were doing this.