Converted CJ2 automatic climate to CJ3 manual controls

[mikez71]

1.Remove radio trim. (plastic prybar)
2.Remove switchbank under hvac controls (7mm socket)
3.Remove HVAC module. (7mm socket)
4.Re-pin/de-pin ~11 wires shown below (pin removal tool or fine pick)
5.Wire illumination wire from J1-4 switchbank plug to J2-1 HVAC module. (1 or 2' of wire and some splice connectors)
6.Wire evap temp sensor lo-ref to J3-19 (in progress...)

CJ3 Manual HVAC module
-----------------------------
Looks like '07-'09 have different climate control part numbers than '10-'14. So purchase the right one!

J2 PLUG
----------
Manual climate control J2 connector is blue, the original automatic J2 plug is black.
It will not plug in directly, but looks like it would with a little modification to the lower alignment slots.

I de-pinned the wires, intending to re-pin them to the new connector. Reversible if problems.
The '07 plug I purchased has different pins than my '12 model.
I ran the new J2 pigtail wires through the original unplugged pin receptacles, then heatshrinked around each wire/receptacle.
(I have since acquired a 2013 J2 blue connector which will accept the original pins from my 2012)

To remove the pins, first remove the retainer (J1 plug, pin style shown, enclosure retainer on older connectors)


Insert a small pointy tool pointing to the bottom of the "T" slot, then pry upwards pointing to the top of the T to release the plastic tab holding pins in.
Pull wire out while holding tool. (ebay pin removal tool shown)



WIRING CHANGES
---------------------
auto CJ2 (BLACK J2) -> manual CJ3 (BLUE J2)

J2-1 (RD/WH) -> J2-4 (HVAC BATT)
J2-8 (BK/WH) -> J2-3 (GROUND ZONE 18)
J2-9 (OG) -> J2-2 (HVAC MAN RUN)
J2-15 (BK) -> J2-10 (BKLT GND)
J2-10 (WH) -> J2-8 (RR DEFOG RLY CONT PWR)
J2-4 (L-GN/BK) -> J2-9 (OUTSIDE AIR TEMP)
J2-16 (D-GN) -> J2-12 (TEMP SENS COM LO REF)
??????? (???) -> J3-19 (EVAP TEMP LO REF)

These are repinned in original connectors.

J1-18 (PK) -> J1-8 (PAS AR TMP SW SIG)
J1-19 (GY) -> J1-18 (RR MOD MOT SIG)

J4-6 (GY/BK) -> J4-5 (LOW REF)

This wire needs to be added for backlighting.
I spliced from switchbank wiring, also yellow wire.

+(BCM MBEC)BKLT -> J2-1 (HVAC LED BKLT) (YE)
-------------------------------------------------------------------------------------------
The wire below is UNUSED in the manual controls, *but* the module does have a pin in that location.
***UNPLUG*** this wire just in case!

--J3-3 (PU) RECIRC DR PSN SIG
-------------------------------------------------------------------------------------------

Wiring from a stock 2013 manual CJ3, some wires are for the rear roof mount dial controls, which are unused on my truck.

------------------------------------------------------------------------------------------
Two wires show up in the '07 and '08 diagrams, but they are not in my '12 Tahoe.
On the '07 Avalanche plug I used (BLUE J2), there was a J2-6 wire, the J2-14 maybe on '08-?? models. By 2012 both wires are gone.

J2-6 (D-BU) -> J2-5 (AC LO PRS SEN SIG)
J2-14 (L-GN) -> J2-15 (COL LVL SW SIG)
------------------------------------------------------------------------------------------
Unpopulated pins shown. J4 pin 1 and 9 are hidden, they are vacant.



Big "THANK YOU!" to everyone who helped out!

 

[89Suburban]

Any pics? Diagrams? Appreciate you sharing.

 

[mikez71]

The factory '08 HVAC diagrams are about 8 pages each, with extra temp sensors and different pinouts being the main differences.
Mostly need to compare both Page 1's (353, 364), and manual Page 6 (369) with auto Page 7 (359).

https://www.gmupfitter.com/wp-content/uploads/2021/05/2008_LD_ElectricalPickupsChassisCabs.pdf

UPDATE: Prefer to use this site for update wiring diagrams..

Free Service Manuals for Chevy Truck vehicles | Operation CHARM

Detailed repair/service/workshop manuals for almost all Chevy Truck vehicles, including electrical diagrams, recommended bolt torques, and estimated labor times.

charm.li

Evap temp sensor lo-ref originally spliced with other temp sensor lo-ref and connected to J2-16.
Will need to find the factory splice connector and reconnect to J3-19.
J242 splice connector is listed as being in the hvac wiring harness.
Evap temp sensor should be upper right side of HVAC case.

Looks like I could also connect to the 5A junction block. As the lower temp sensors connect to vacant pins, don't need to worry about disconnecting those.
-WILL UPDATE-


#15 is where the J206 splice should be...No idea where J242 is..

 

[mikez71]

https://i.ebayimg.com/images/g/D7oAAOSwj-dlxhp0/s-l1600.jpg

Link showing most of the wire colors and locations. It seems to show the wires as listed in the '08 diagrams..

 

[j91z28d1]

what diagrams are you looking for? I can look up. what my software shows.

 

[mikez71]

Looking for the 2012 manual HVAC. Think I found a free site here someone posted before....

HVAC - Manual — 2012 Chevy Truck Tahoe 4WD V8-5.3L Service Manual | Operation CHARM

Detailed repair manual for the 2012 Chevy Truck Tahoe 4WD V8-5.3L.

charm.li

I feel like the wiring should is correct, these are the codes I'm getting..


B0433 61
- Temperature Control 3 Circuit Actuator Out of Range / Stuck

B3782 61
- Air Flow Control 10 Circuit Actuator Out of Range / Stuck

Rear roof vents stuck off the last time I went for a drive, when previously they were stuck on.
I was getting about ~5V on J1-8 and J1-18, but still unable to control rear temp or rear mode.

------------------------------------------------------------------------------

Tech2 showed commanded door positions properly, actual position varied very little.
Showed commanded aux temp. +0 to +12 equaled 0 to 255 'counts'. But temperature did not change.
Changing the aux mode would command 0, 115?, or 255 and seemed to work at turning off roof vents in face position.
But actual 'sensed' door position changed very little.

Have done actuator relearn procedure a few times.

J4-2 (5V REF for both rear aux actuators). J4-2 did not change positions/purpose.
My measurement would quickly drop in voltage. Would not show 5V using chassis ground

J4-5 is LO REF GND. Not sure how to test these?

 

[j91z28d1]

this is a 2012 5.3 manual hvac. hopefully the quality is good enough to read.

 

[mikez71]

this is a 2012 5.3 manual hvac. hopefully the quality is good enough to read.

quality is great! Thank you.

Looking at the auxillary mode and temp. Wiring seems correct, not sure what I'm missing. Will take more readings tomorrow!

 

[j91z28d1]

cool. left me know if you want me to look anything else up.


I ordered one of those OBDx dongles that might be able to let you flash the truck to setup it up for manual? unless the tech 2 will do that.

 

[mikez71]

Don't think Tech2 can program, keep me updated on the OBDx device!

Checked my 5V REF (J4-2) to LO REF GND (J4-5) reading 4.8V with key on engine off.

I'm just trying to understand how to test these actuators. Starting to wonder if I could have damaged the module from plugging it in before I had repinned anything.