Recent Content by Christopher McKenna

In supporting another thread on here regarding HVAC / Thermistor Assy related issues, I generated a very simple rework document for that thread. I am uploading here for convenience for those who come across this particular thread so that they'll have access to it here as well. Regards, CM

Having diagnosed the controllers in the past, there were defects involving P2, the smaller input control side connector - not the high current blower motor mains connector. Remove controller from vehicle and open the injection molded snap shell. I'd do this on an ESD mat tied to a 1M Ohm...

Just seeing this today - sorry for the delay here. You're welcome BC. Hope it works out and works reliably as well without faulting like it was prior. Regards, CM

The HAD / HAA in the photo is upside down thus, the placement of the probe shown in the incorrect position - also as seen / shown in the User Service Manuals till this day, show the bottom side of the EVAP CORE not the top side where the plumbing exits the HAA unit through the firewall interior...

I got mine second hand from a Mom & Pop flip-this-truck joint in TN and, drove it since 2011 till about oh, 2017 without maintaining it. Mostly cross country back and forth non-stop till deciding to change injectors after noting a rough running and slight smoking condition. Once I started down...

So what we've got here I'll bet is, the No 1 Root Cause for ice up that the original owner reported as occurring to him as well. This goes back to a design issue / error. Using logic here, I am willing to state that, I'll bet that once you relocate the OEM thermistor probe to the correct...

This is out of the service manual - thus, as shown, the thermistor probe location is in the upper right hand corner. This is where the root of all the ice-overs emanated in the beginning starting with design and whomever the tech writer was that worked on the HVAC section for the manual. This is...

The ice-over condition at the EVAP CORE, on 2003 models, per engineering, was due to a misplaced thermistor probe. That was the root cause for freeze-ups. The engineering firm that caught the error in the wild through mechanics had notified dealerships all over the country about the error...

There we go. Now then, with this in mind, I'm curious as to what the thermistor assembly looks like that mates up to this controller. I'm wondering about something seeing how this is a different configuration controller. Has the vehicle always iced up since you've had it? Do you happen to...

That's the older controller model. Can we get a part number / PN for this one please? That way, we'll have the PN on hand to which, can be accessed herein this thread and the database I've been compiling. Thanks, CM

Hello again BC. Do not run two thermistor assemblies concurrently. It's the equivalent of running two resistors or caps in parallel thus, the circuit will MALFUNCTION. I am 100% confident failure will occur. The driver circuit is designed around a 5V reference signal. It cannot handle...

I'll bet, once the sensor is located in the correct flow lane, the controller (if working properly), will finally see proper input thus, it will finally be able to control the compressor. What had occurred back then, was an inversion, which wound up as a misprint in the OEM manual with regards...

BC: Upon looking at the data there, it's immediately recognizable on my end at least, that we've got the same type of component sporting the same R25 value. The AMB TEMP OHM reading indicates both components inside the probe are 5K. Both probes are NTC Types (as are most in HVAC systems)...

Bobbycat, Let's get the images of both sensors into this thread for documentation purposes. I've been compiling a configuration matrix and would like to upload the images. I always wondererd how far back this 3rd gen HVAC sensor design went to the point engineering rolled out the 2005.5 -...

Bobbycat, Sorry for not getting back to you sooner. Torn rotator cuff on me end has made everything difficult. Let's walk the path and root things out by ruling out as we go. VERIFY PROBE COORDINATES Ensure x and y placement matches what's shown on the super-imposed photo for thermistor probe...