Hiya folks, I've had a problem with no heat coming from the vents in my 500. The 420's heat is fine so I just swapped the duovalve between the two. Makes no difference.
It's worth noting that on a hot day, with the heat on "HI" on both sides, the air coming from the foot well vents and from the center console (for the rear seats) seemed to be as cold as the air when I chilled it down to "LO". Even though the compressor obviously wasn't on.
The heater core could be clogged. COULD be. But this is a '99 with 70k miles. There's no corrosion or sediment evident anywhere in the cooling system, and I've replaced the water pump, and done various other things that drained the coolant. If it was a '94 or '96 and had 150k-200k miles I'd think it's plausible but as it is, I just do not believe that there's a blockage in the heater core. I'll end up ripping out the dashboard, putting in a new heater core, and find out that I still have no heat.
Here's my question: What ELSE could cause no heat whatsoever? I'm assuming there's a cabin thermometer; what if that's faulty?
I pulled trouble codes from the climate control a couple of days ago and came up with Eb1 231 (ECT sensor) and Eb1 234 (Sun Sensor). I have a new coolant temp sensor on order, should arrive in a couple of days. I have not had any of the codes recur in the last few days. Could an engine coolant temperature sensor on the fritz cause this? I'd assume the sun sensor cannot.
Could this be a problem with the vanes in the duct work?
I can believe there's an electrical problem, but I'm just reticent to pursue replacing the heater core until I've eliminated all less invasive possibilities.
Is there any definitive way to determine whether the heater core is clogged without removing the dashboard?