Heater Valve

The heater valve operates differently with the dcc setup. The normal setup varies the opening with air mix cable. The dcc leaves the valve open all the time and closes it when the temperature is set to max cool or 18c. It does this through a vacuum actuator connected to the heater valve instead of the normal cable. When max cool is selected, the solenoid is opened allowing vacuum to reach the actuator which closes the heater valve.

While I think the stock accord cable setup will work fine with the dcc, I still went ahead and installed the vacuum setup as it was designed.

The dcc heater valve uses a different arm for vacuum actuator. The keyway on both arms are same, the vacuum arm will bolt on in the same spot as the stock cable actuated valve. Unfortunately the heater valve itself needs the arm in a different spot to open and close properly with the vacuum actuator. So the accord cable heater valve has to be changed to the vacuum heater valve


The heater valve arms cable on the left, vacuum on the right


Heater valves fully closed. Accord cable heater valve on left, TL vacuum heater valve on right


I placed the heater valve solenoid with the emissions solenoids. It really doesn't have any room the mount the solenoid but it will wedge in tightly after the casing is cut down. Remove the vacuum hose from one of the existing solenoids and connect to the vacuum 't' that came with the new solenoid. Connect the other two sides of the 't' to the new solenoid and
existing solenoid. The heater valve solenoid output hose is routed to the bottom of the emissions casing and exits through a new hole I drilled.


TL heater valve solenoid before trimming bracket


Tl heater valve solenoid after trimming bracket


#20 hose the needs to rerouted to 't' as source of vacuum for heater valve solenoid


Heater valve solenoid wedged in


Vacuum 't'd in


new vacuum hose from 't'


Heater vacuum actuator hose running out the bottom

wiring
Cut the black vinyl tubing so that there is just enough left to cover the wires on outside of emissions casing. Cutting the vinyl also makes it easier to run new wire through to the 4 pin connector.

Wire the blk/yel solenoid wire to existing blk/yel power wire.
wire the yellow solenoid wire to dcc pnk/grn

Run yellow through the vinyl tubing and into the open terminal spot of the 4 pin emissions connector. Then add a pin into the other side of the connector and run wire to the dcc. Use the fog light wiring grommet below to route wire inside. Add a 3 pin connector to unplug for servicing.


Empty terminal slot on 4 pin connector.


Filled terminal

With the emissions box still removed, remove the fuel filter bolts and charcoal canister to access heater valve. Remove the heater valve and replace it with one from the vacuum actuated heater valve. Cut the TL bracket down and mount together with stock accord bracket by heater valve screws. I welded the two brackets together with a reinforcement plate for extra support. Run the vacuum hose to the solenoid.


Tl bracket bolted on accord bracket before cutting


Tl bracket and accord bracket welded together and reinforced


TL heater valve installed

That completes the basic setup and you should have working fully working heater and a/c. If you want to make the auto climate control work, the rest of the sensors(sunlight, evap temp, outside temp, interior temp aspirator, coolant temp, and vss) need to be installed.

Evaporator Temperature Sensor
Any evaporator temperature sensor from a Honda climate control system will work. Electronically they are all the same. I used one from a 1st gen Acura CL. The evaporator temp sensor goes into the evap housing on the heater side. The CL sensor has a clip on it that mounts into the fins, fifth row in. My a/c was already discharged so I removed the evaporator to make it easier work on. It was actually pretty dirty inside and couldn't be cleaned properly without removing it. The evaporator has a temperature switch in it already that is not used on the dcc system. Unplug the temp switch and connect the wires together to so the a/c signal will pass on. I just left it alone as another safety.I drilled a hole on top the housing near where the original temperature switch enters. I used a temperature switch grommet to pass the sensor through and seal the hole. I also drilled a hole in the housing tab to clip the connector on.

wiring at evap temp sensor
brn to dcc brn
yel/grn to dcc yel/grn


Wiring passing through new hole and accord grommet, connector mounted to housing


Evap sensor clipped in to evap core

Outside Temperature Sensor

The JDM CB7 outside temperature sensor clips on to the bumper. This style of sensor can be found on the 1st and 2nd gen Legends but any outside temperature sensor from a Honda climate control system will work. Electronically they are all the same. I used one from a 1st gen Acura CL with the plastic casing and an actual bolt down mounting bracket.

The outside temperature sensor mounts on the core support behind the bumper grill opening. I actually mounted it towards the passenger side of the bumper opening to a power steering cooler bracket bolt. Run both wires back to the dcc. Follow the same path as the fog light wiring harness and through the 3 pin connector from the heater valve wire.


Outside temperature sensor installed

wiring
brn/wht to dcc brn/wht signal
yel/grn to dcc yel grn sensor ground


Sunlight Sensor

Any sunlight sensor from a Honda climate control system will work. Electronically they are all the same. The sunlight sensor goes on top of the dash either in the center or off to the side. I used one from a 1st gen Acura CL/6th gen Accord since it would mount the best. Make a hole in the dash between defroster vents and clip it in. This will take a bit of time since the dash is metal between all the foam.


Sunlight sensor installed


Sunlight sensor from back of dash

wiring
wht/red to dcc wht/red signal
yel/grn to dcc yel/grn sensor ground

Coolant Temperature Sensor

The coolant temperature sensor for these older systems is actually in the heater housing and does not use the signal from the engine like newer ones. The sensor mounts against the heater core inlet side. This requires removing the heater housing to get to the heater core. I used a sensor from a 2nd gen legend. 1st gen legend will also work and is much harder to remove out of donor vehicle.


1st and 2nd gen Legend coolant temp sensor

The sensor will fit under the heater core cover but the cover still needs to be trimmed to fit back on a bit better.

wiring
pnk to dcc pnk signal
yel/grn to dcc yel/grn sensor ground



Before coolant temp sensor


Coolant temp sensor installed

Interior Air Temperature Sensor

The interior air temperature sensor is built into the bottom right corner of the controller but still needs air drawn through it to work accurately. The accord uses a small fan mounted on the outside of the heater box connected by a hose to the controller to draw the air. The fan is wired directly to ignition power. An identical fan can be found mounted directly on the gen2 legend climate control unit


2nd gen legend fan

On newer models the sensor connects through a tube to a nozzle(aspirator)mounted to the heater housing, the air exiting through the aspirator draws air through the tube. There seems to be different versions of aspirators in every generation. 1st gen CL and 6th gen accords aspirator mount on a male protrusion the heater housing. The 2nd gen TL has the male part in the aspirator and just a plain hole in the heater housing.

I chose to use an aspirator from 2nd gen Acura TL . It needs to mounted in a spot where air is constantly flowing and not closed off by any of the diverters. Meaning after heat/cool blend doors but before the hi/low/defrost diverters. I decided to mount it in the front corner on the drivers side. The aspirator uses a corrugated flexible plastic hose to the sensor or a tube union. This hose not long enough or sized to fit the dcc. I used a tube union from a 1st gen Acura CL. From the tube union to the dcc, I used the matching rubber hose from a 1st gen Acura CL.

Cut out the odd shape of the aspirator inlet in the heater housing. Use a screw to secure it. Route the matching corrigated hose from the side of the heater box and secure the tube union. Run the ruber hose from the union to the dcc.


Heater box before aspirator


Aspirator hole cut out


Aspirator mounted

Attach the clear flex tube and union to the aspirator. Drill a hole in the heater housing for the tube union locator pin. Then secure the tube union wth screw. Attach generic rubber hose to the other end of the tube union and route towards passenger side. Cut a small 90 degree piece off the molded rubber hose and attach to the dcc. Connect the generic hose and factory hose together. I used aluminum tube and flared it on one side since hoses are different sizes.


aspirator hose


pieces for the dcc


connected

Speed Sensor
Finally connect the vss wire to cluster. Since the dash is out I ran it to the cluster to keep the wiring inside the dash.

dcc org to cluster org bottom left connector



Now put everything back together and enjoy unless you want to be ultra cool like me and add steering wheel controls to your dcc



Steering Wheel Control of DCC
Remove the dcc and disassemble. Solder wires to the back of switches for temp up, temp down, fan, mode, auto, and off. Run the wires to a relay for each switch to be used. The buttons on the steering wheel will trigger the relays which will act like pressing a button on the dcc. I used small reed relays so I could fit them inside the dcc unit.





I modified the switches of my 2009+ Tl steering wheel so instead of 3 switches on 1 wire, I have 3 discreet output wires.

3rd post

Are you for real right now? This is some legit work man.

Great job. And thank you for taking the time to make this very informed diy.

This is madness!!!!!


Very well done, (still one of the hardest mods out there for the CB)....You have video as a proof that actually works and your DIY very well detailed.....


It's good to see knowledgeable people willing to share, You took your time doing this DYI, taking pics, and remembering every single detail....


Well done once again Lucifer.... is that your actual nickname or something? LOL

Amazing work. Most of us are in awe of what your capabilities are when it comes to figuring out difficult projects. Thank you for taking as much time as I know even just this post took to contribute to this site. For those of us that have actually analyzed the issues presented by this install and the components theoretically required, we know exactly how difficult this was to come up with all of the information and assemble different parts to try them out. Not many people here will truly understand what you have invested in this and will still hope to order some parts and do it in a weekend. Bravo, good sir. Bravo.

One question, though. You mentioned that the older style units did not measure an engine temperature at an existings coolant temperature sensor, but inside the cabin. Why can't you simply obtain your signal from the sensor on the engine or a fan switch anyway? Would it be hotter at those points and outside of any parameters that the DCC would know how to handle? What's the reason?

Why does the system use a light sensor?
Can you turn off those beeps?



Nice write up btw.

Ptetty much, I thought about using an engine sensor but figured the temps would be different and the dcc was designed around a specific spot. That coolant sensor is also used by Range Rover in late model vehicles.

I would think to better calculate air temp and fan speed. Higher fan speed with more sunlight to cool faster.

I don't know how to turn off beeps, but you could remove the beeper from inside.

You. Are. Amazing. Thank you so much for all you've done for the CB7 Community!!!

Simply amazing work!

I was considering using a ton of custom electronics but it looks like you got it all mapped out with OEM parts. Great job!

Good work man. This is a lot of work and dedication. Hopefully someone will follow this and do it. I might someday.

Wow very intense and detailed work!

Reminds me to try to do something. Cpmike and I have been having so many extra parts but never attempted!

Thanks!

Awesome writeup. Thank you!