Dual climate control blowing heat on AC (DCCV removal instructions in post #107)

[gsuburban]

Much obliged Rod. I performed both of these however, nothing happens. My main goal in this was to get the "calibration" task completed as part of this "reboot". The display remains as it is, no codes, no other changes occur. I also found this on Lincolnvscadillac.com as I visit both forums for information. Thanks for being there on this.

So, after thinking this "procedure" over I tried a difference sequence than I had been using as I was pressing OFF and FLOOR buttons simultaneously but holding them both in then pressing the AUTO button. Don't know where I figured that was the idea but it is incorrect. Pressing OFF and FLOOR buttons simultaneously then release then press the AUTO button and it enters the diagnostic process.

All working now that I have the correct procedure with the buttons. Oh, no code after going though all 25 readings so I guess all is well with that control unit. Thanks to everyone who added their input to this post.

[Wrabit]

This is an epic thread with lots of info!

My '01 Jaguar S-Type's A/C blows cold on driver's side, warm on passenger side. I used scanner & found DTC b1966 (discharge air temp sensor circuit failure). I also performed clamping of the 3 hoses to check DCCV. Didn't make a difference.

I've been told I should just replace DCCV because they're prone to failure, & to ignore b1966 code.

I've read the discharge air temp sensors data is used by the A/CCM to determine control of DCCV allowing system to provide individual discharge air temp to driver & passenger sides. Doesn't the b1966 along with the issue I'm having sound like the cause is the sensors/circuit, or could it be a bad DCCV?

Thanks in advance.

[shorod]

Yes, I would definitely change out the sensor before the DCCV, especially considering the testing you've already performed. The sensors are inexpensive (around $25, assuming they are still available) and pretty easy to replace. Depending on how much you value your time, it's almost more cost effective to replace the suspect sensor than it is to really diagnose them.

-Rod

[Wrabit]

Thanks!

The scanner correctly identified the discharge temp sensor fault. I found the d/s discharge air temp sensor to have infinite resistance. Had to order one. Hasn't arrived yet.

Checked voltage at p/s, d/s, & evap discharge sensor harness connectors & found evap is at 4.66v. LS specs are 4.7-5.1v. Jag specs are '5v nominal'. Should I be concerned with the evap sensor voltage supply being only .04v below what LS FSM lists as minimum specs? Can't find spec info on minimum Jag voltage.