1998 E300TD - No heat
 

Good Afternoon,

This forum has been great and I have learned quite a bit about my new to me E300TD.

I have followed the Climate Control threads closely and have searched for my particular fault without success.

My AC appears fine and works without a problem. I have recorded actual values and pulled codes through the system without a problem. Nothing unusual.

The Defrost works and pumps heat out without issue.

When I call for heat only (78 or 79 F) and the car fully warm, I feel cool, ambient air flowing, not heated air. This morning, I tapped my Duo valves to see if they were stuck and I had warm air for my trip into work. However, the ride home produced no heat. I will wait till it cools down before disassembling the duo valves to see if they are stuck. This car had one replaced in July of 2005 (new).

No abnormal fault codes - the K2 communication error and the E 'FF' code which I don't know what that is.

I wonder, since I get defrost heat, if I am looking at a door actuator failing?

Your thoughts are most appreciated.

Thank you,

Frank

Suppose you switch immediately from defrost to heat, does the heat come out hot and stay warm?

No, switching from defrost to heat does not make it stay warm. It cools down quite quickly.

Nice! Thanks so much Parrot of Doom. I will try this after my kids go down for bed.

Frank

Last night I partially disassembled my Duo Valve. I could not release the electrical connector, so I simply removed the 5 Torx screws and exposed the coils on the valve.

I gently depressed the two plungers with the coils in place and felt some resistance (stuck) and then they moved freely.

This morning, I checked for fault codes (none) and proceeded into work. I actually had heat today. I will try again on my way home. Perhaps this is the issue and I will need to clean that valve up properly this weekend.

To pull the connector off - should I gently peel the tabs up and pull? Or is there a locking mechanism in place?

Regards,

Frank

Look at the 2nd piccie in my guide, just squeeze at either end and it should pop off. It may help to get a small screwdriver in there and release the tabs manually.

Just a follow up from yesterday's post :

Heater is now operating as normal. So apparently, the Duo Valve was stuck.

I will need to pull the electrical connection and do a proper cleaning on the valve. What lubricant should I use? Perhaps a real light weight oil on the surface of the valve and seat?

Thanks all.

I used anti-fling spray oil, it was the first thing to hand and its rather sticky oil. Seemed to make sense to me, and I haven't had a repeat of the problem.

Oh and that will be £10 please. :)