The probe sends the evaporator temp to the control module and the programming in the module controls the cycling / temp. IMO.
The relay lets you control the cycling thru the vent temp.
I have set the relay to 32 degrees and the vent temp dropped to to 30 degrees, the vent stopped blowing. So I reset it to 38 degrees to keep it from icing.
In early a/c systems they had a orifice tube and the compressor never cycled, it stayed engaged.

 

No I'm sorry! I meant how, when and where do you look for the ambient temp?

 

The ext temp displayed on the center console? I Don't know if it has anything to do with the a/c, maybe thru the control module.
Right now it's 84 degrees and vent temp is 38 degrees, relay is set at 4 degrees C.

 

On mine, while it never gets as cold as my sons explorer or wife's edge, on my f150, things really go south when the display indicates a temp starting at 79, some times.

 

Is this correct regarding the chart: if the outside temp is say 95 degrees f, then the evap probe should read in the range of 19' 2 to 19,8? Is this ohms taken while on or off?


My guess as I have stated before, there is something on my truck that is telling the probe to operate differently or I still have a defective probe on the new coil that was installed.

 

If the control module is using the ambient air temp to control the evaporator temp then the cycle time would increase to compensate for the hotter outside air coming in. If in recirculate mode a shorter cycle time for the cooler air coming in from inside the cab. IMO.. The probe or the program set points of the module. IMO! My Speedo just turned 199,000!

 

Turn the truck off, unplug the probe, using an ohm meter test across the 2 contacts on the side going to the probe. The ohm value should be close to the inside cab temp... Compare temp to ohm reading in chart.

 

Thanks that's what I think needed to be explained!

 

I went and watched the two videos that cool that it works. I need some pics to see how to hook it up.

 

Mine is scheduled back at the dealer on Tuesday. If its not resolved, I am reactivating the original BBB arbitration that I filed last year before they replaced the evaporator.