Guys

I was under the impression, DCCV solenoids are de-energized shut. Meaning,when no pwr is applied solenoid are shut, and no coolant flow to heater cores on driver and Pax side.When CCM needs coolant flow into the heater cores, it will ground the circuit there by having a path for current to flow, energizes the solenoid.When solenoid is energized it opens the ports, for coolant flow to heater core.Reading the wiring diagram for DCCV (valve side )has 3 pins. Center pin has power.Lh and rh pins ground per the demands of CCM engerizing the respective solenoids.

I cannot find in JTIS, if this is the correct valve operation, or opposite to it, meaning,soleniods are always energised with igintion on, closing the ports preventing coolant flow.when CCM needs coolant flow to the heater core it takes the power , de energizing solenoids, there by opening the ports, for coolant to flow to the heater.

Can someone shed light here, which is the correct operation of the DCCV?

Note- Reading a TSB for 2000-2002LS( which shares the same DCCV),lack of cooling due to DCCV( 03-3-4),it states if you measure the resistance of the soleniod, it shud be between 13-20 ohms.Did jaguar put out a TSB for DCCV issues? Atleast ford did?

 

I think they default to open which is why there's too much heat.

 

jagv8 is correct - The Dual Coolant Control Valve (DCCV) is "default to open."

Center pin to the Dual Coolant Control Valve (DCCV) always has power (from the fuse box). The Climate Control Module (CCM) is active low, so it sends a Ground "signal" to the LH and/or RH pins on the DCCV to energize the respective solenoid inside the DCCV.

Normal Operation:

• Temperature setting "Lo" = CCM output ON (grounded) = solenoid ENERGZIED = solenoid valve CLOSED = coolant flow to heater core impeded = heater core NOT HOT.
• Temperature setting "Hi" = CCM output OFF (open circuit) = solenoid NOT ENERGIZED = solenoid valve OPEN = coolant flow to heater core allowed = heater core HOT when coolant is HOT.

Note: Even if the Climate Control System is turned off by the user, a functioning CCM will keep "CCM output ON" so that the cabin doesn't continue to heat up unnecessarily.

Solenoid resistance measurements of 13-20ohms, or less, should be reasonable. However, measuring the resistance of the solenoid may not have much meaning by itself. Unless that solenoid (coil of wire) is physically broken/disconnected, you'd essentially be measuring the resistance of a just that -- a coil of wire. Because it is an inductive load, you must also measure its current while energized. I've seen current measurements in good DCCVs range from 0.6 to 1.0A per side. I've seen bad ones measure as low as 1.1A (on 12.0V) to as high as 6.5A (on 14.0V). That 6.5A solenoid still opened and closed, but it was attached to a stand-alone power supply on my test bench. No CCM could handle that level of current.

So, to find out of a DCCV is electrically OK, take those current measurements. This can be on the bench with a separate power supply, or, if it's still in the car, you can jumper the LH or RH pin to Chassis Ground with the meter while listening for the solenoid clicks.

 

Hi jagclimate control

Below are the steps i did to isolate my issue, of no heat (V8-2000S)
1. Jumpered a wire between ctr pin and plug,after disconnecting it from DCCV.Ctr pin to chasis ground, with ign off reads 12V +.
2. also connected jumpers for LH and RH pins on DCCV( Vlv still installed in the car),connected meter between LH wire and ground 0.71 A, on RH as well.(pwr was avl to the ctr pin, with jumpered wire from plug-12V).
3. I was not getting any current reading when i connected the other lead of the meter to the plug LH pin,instead to the ground.RH was the same. If CCM is grounding the circuit to keep the solenoid energized, i should see current flow. correct?----Pls your input?
4.Also placed the meter in OHms range, checked LH pin in the plug to ground, for continuity- no reading. I assumed,if CCM is grounding LH pin on the plug,i should see continuity, when i i place the other prong of the meter to grd, correct?- your input pls?
5.When i grd the LH and RH pins,( step-2 above), i don't hear the solenoid clicking either?

Can you advice how i can check if the circuit is getting the proper grd through the CCM,if above steps i did was noth the correct ones.

I am confused now if it is the CCM,DCCV or a bleeding issue?

 

I don't understand you. In #2 where did you connect the jumpers? And did you connect bothjumpers and the meter on its amp setting? Why?

Best I can tell from what you said is that your DCCV has burnt out solenoid coils.

 

Ok so from what you're saying... You jumpered LH AND RH pins from dccv to a known good ground. did you hear the individual solenoids click when they operated.

Second current usually requires a different input on the multimeter and you just wire the meter inline with the connection. you can't test current while backprobing the plug plugged into the CCM. Current should be around 1.0a max on either side.

With the wires plugged in to the CCM, to check proper CCM operation, the center wire should show +12v and the two outer wires should show open w/ AC on, and continuity to ground w/ max heat selected. Current should be around 1.0a max on either side.

George

 

George/jagv8/jagclimatecontrol

picture says a thousand words.You will better understand looking at the picture, and what itried to accomplish.your inputs please.[ATTACH]File0049.PDF[/ATTACH]

 

Nice drawing mel.

Step 1 looks good.
Step 2 0.71A is acceptable. You should hear the audible click. It will work with engine off too, to help you listen for the click. No audible click to the heater core here means the DCCV has problem(s). No hot air at the vents means the heater core is not getting hot/warm coolant.
Step 3 No current reading here means either the DCCV, harness, connector, or CCM has problem(s).
Step 4 No continuity to ground here means either the harness, connector, or CCM has problem(s).

If the DCCV isn't getting power at the center pin or ground at the RH or LH pin, then it should default to allow coolant flow to the heater core. But if you aren't getting heat at the vents at all, then somehow, the DCCV is not defaulting to the expected state. It is quite odd...

 

hi Jag climatecontol

i was on vacation,sorry!
1.i have amp reading of .71 on both solenoids, so can i eliminate dccv been bad.
2. i suspect CCM, what actions can i do to check if CCM is bad
your thoughts
rgds
mel

 

Your Step 3 and Step 4 tests already suggest fault at the CCM. But if your problem is "no heat at all," then try checking the 1 input and 2 output hoses from the DCCV. Disconnect the connector at the DCCV (this keeps it powered off and also bypasses control by the CCM), all 3 hoses should be warm/hot.

 

Hi Jagclimate control

My issue is no heat. AC works fine.heat is not a issue since i live in los angeles, but comes handy during latter months of the year. I will try removing the plug for the dccv and running the engine.if the 3 lines are hot i can eliminate the dccv.
1. if i place the meter in volts range, and place the prongs on the dccv connector-side center pin and lh or rh pin, (assuming ccm fully cold setting or ignition not on), i shud read 12-13 volts, if ccm is correctly grounding? shud this be a good test to chk the ccm grounding function.

Also so many people have issues with this if you are willing we can include T/shooting steps to isolate individual components, and save money for the folks here/ i read so many blogs, after replacing components, they have the same problem.

your thoughts
rgds mel

 

Mel:
When you say you have no heat. Is it all the time? One other part that might be causing your no heat issue is the AUX coolant pump? The symptoms of this failure is no heat at idle or low speeds but heat at highway speeds.
I did not see if you have this happening or not?
.
.
.

 

clubairth1

I have no heat at any rpm. i used a stethoscope to listen for pump operation, and it works as advertised.this is a handy tool have, 5 bucks at harbour freight. Also the plug is accessible and can check the voltage as well.