A/C Performance during Highway Cruise

@CurtB - I gave gauges back to my friend over the weekend... From what i have researched on this forum and looking at the FSM's there is not a low pressure switch. I can't locate one either when I look for it, my only guess is they planned on the thermistor to prevent freeze ups and maybe they didn't care about low charge/loss of charge protection? I was surprised it doesn't have LP switch

 

Thanks Curt! I was able to locate that one but its a high pressure switch on the high side of the system. From the document it will trip on abnormal high pressure (455psi) or at extremely low pressure(28 psi) on the high side of the system, that must be what they are using for a loss of refrigerant protection.

I hope my new thermistor comes in today so i can verify my sensor against it for one last verification before I take the dive into the dash!

 

Yes, it's a dual switch. And...

I'm an idiot. If the pressure was low enough to trip the LP switch, there would not be enough freon in the system to freeze up the evap. You are on the right track about the thermistor. sorry for the bad advice.

 

If you read the thermistor with a meter and followed the procedure and are getting a bad reading there isn't much wiggle room. It's bad it needs to be replaced.

 

Thanks, not sure why but I needed to hear that!

 

@Jimmyh @CurtB

Well i picked up my new sensor today, verified what we expected it was way off (1k ohms off) on resistance compared to new one.

I have been studying the design of the evaporator box and all the dampers/servo's trying to find a way to not take apart the whole dash which to me seems silly... After doing my research and watching many video's and looking at pictures I made the decision I was going to drill a new hole about 6" lower than the factory sensor to install. It will still put it on the face of the evaporator and in the air stream before any dampers. I put the hole in a place where i knew it wouldn't hit the evap adn drilled VERY slow.

It is working as expected installed in the new location. I know some may say this is not per OEM and this might be half-a$$ing it but i wanted to give it a try first and it works. All i could do is mess it up and still have to take the dash apart.

Green arrow is the factory installed one, red arrow and circle is where I put the new one.

 

As Plato said, Necessity is the mother of invention.

As long as it works and doesn't cause a freeze of the evaporator I would say good job.

 

What is the spec for the sensor and where did you get it from?

 

not sure on specs, it’s been too long. I got it at the dealer for under $15

 

hate to wake up an old thread, but to OleTaco is this modified fix still working?

Im currently dealing with the same thing.