Ok folks, after 15 months of ownership and over $2000 in repairs and maintenance, my patience is really being tested with Jaguar ownership (see my other posts - blower fan, air shock, headliner, heater core, etc. This was a one-owner, dealer-maintained car in excellent condition. I know that Fortress is having the "no drivers side heat issue right now" and I noticed tonight that my 2 drivers side vents are noticeably cooler than the passenger side. What's really heartbreaking is that the heater core was just replaced about 3 weeks ago & when I got it back, the drivers side heat was BLAZING hot. What the heck guys? This is really frustrating. It doesn't show low coolant or anything. Any thoughts? I really don't want go go through another $1000 "guess what's wrong with the jaguar" escapade. Is it possible that the new one is clogged? Surely not. Blend doors? Who knows. Advice is appreciated.

 

I am hoping the best for you, that it is a problem with a temperature sensor. You will need a good scan tool to determine which one. Or you can pull them out and test them with an ohmmeter. Resistance at room temperature is about 23K ohms. These sensors are about $15 each. Most likely the one on the driver's side has failed.

If it is not the temperature sensor, then perhaps the DCCV (dual climate control valve)?

These things are notorious for failure. And when they go, the climate control module is taken with them.

I believe the problem stems from owners or shops (not you or yours in particular) mixing antifreeze types. When the orange antifreeze is mixed with the green antifreeze, the solution congeals. Not in a jello way, but enough to make flow through heater cores and especially DCCV valves difficult.

Additionally, the DCCV valve has components that might be suspended in the congealed solution, that is, if it has internal leaks to the solenoid plunger. This could cause the plunger to be sluggish or stuck in the solenoid body, thereby increasing the load on the solenoid, and hence the current through the SCR in the climate control module.

I am sure the techs will respond to this post, and maybe tell me I am wrong. But this is my suspicion and if it was my car I would check the temperature sensors first and the operation of the DCCV second. (I already have checked my S Type, just to see the condition of my DCCV)

The reason you are not getting heat is either because:
1. Temperature sensors are not working. (They do just fail. Mine did.)
2. Fuse for DCCV valve is blown. (may not be the case at all)
3. DCCV valve is stuck in the closed position.
4. SCR or signal trace in the climate control module is fried or open.
5. Blend doors are not working.
6. Something worse (like new heater core clogged up with solidified antifreeze).

The real puzzler for the clogged heater core is why isn't the other core clogged as well?