another revisitation on old actuator trick

[fdryer]

As you know, seniors like to use the phrase "young at heart, old age is a state of mind", etc. I've been informed of my spoken words as sometimes harsh or condescending. The word 'condescend' isn't in my vocabulary. I try speaking straight forward with tact and make extra attempts when writing for clarity.

I can't prove L-series actuators having either a mechanical or electronic memory to return to a default position and presume they're fixed in their last position when ignition is turned off.

[Jim@HiTek]

Matters little to me if returning to defrost is the default or not...I was just curious what was happening with mine since I can't get defrost air in any setting of the electronic controls. Even at 48 F temps (but low humidity). I carefully walked through all the settings on the control...after having read the users guide section about it, but could never get air through the defrost vents.

AND next fall I'll be up in the Walla Walla valley where I'll spend the early part of the winter. Having a working defrost up in that moist valley is going to be important I think.

[fdryer]

^ In a nutshell, heater control malfunctions occur can occur in these areas; wiring, control head if its auto climate control (no cables, linkages to control panel), hvac internal door mechanism and actuators.

[02 LW300]

Bob, when you install your actuator make sure the white plastic cam turns easily. The actuator turns less than half a rotation. The actuator I sent is set in the middle position which is floor. It is held on by two 7mm screws. Hope this solves your hvac problems
Andy

[Jim@HiTek]

Originally Posted by fdryer

^ In a nutshell, heater control malfunctions occur can occur in these areas; wiring, control head if its auto climate control (no cables, linkages to control panel), hvac internal door mechanism and actuators.

Are there any tests to narrow it down? BTW, I don't hear any funny noises inside the cabin when I change functions with the electronic climate controls. I changed the paper cabin filter not long ago and didn't see anything strange or broken inside there either.

I haven't tried to take that inside area apart yet.

[fdryer]

In theory, no one wants to hear the hvac mode, temperature or recirculate doors moving and design sees to that. I can hear the quiet movement of actuators when paying attention to each one but they're not designed to let anyone know they're working. Turning blower speed up, listening for where airflow exits and/or a hand on defrost, face or floor vent are ways to tell if selected mode correlates with air flow. When I thought one of my actuators was acting strange, I used my hand to feel airflow as I went thru each mode to test actuator movement. Member 02 LW300 has tested spare actuators by plugging them into his hvac connectors to ensure each one works (previous replies in this thread). Unless you have a spare actuator for plug n' play, removing one then reconnecting it to its wiring harness and playing with the mode switches may be the only diy troubleshooting method as long as an actuator can be removed to observe the output shaft moving during mode selection. I presume wiring, hvac control head and interior doors of our hvac boxes are intact and in working condition. There's a lot of assumptions on my part and I can be wrong too.

The cabin filter lets you see the recirculate door movement when the filter is removed. I haven't tried to look down the window cowling to see if the temperature and mode door are visible. My guess - the doors are not too complicated for reliability. The actuators doing all the work are, in my opinion, the weak link. Since they easily outlast new car warranty, maybe double the time and/or mileage, they can't be faulted when they fail.

[Jim@HiTek]

Unfortunately, it was said that those actuators shown earlier in this thread are for the analog style comfort controller. Mine is the electronic. I've found the electronic style on eBay and they're like $200...which suggests that it contains the transistor switches for the door actuators. But I don't know yet.

And electronics just happens to be my skill. So I've been trying to find schematics (or rather electrical drawings) of the electronic system which will tell me if there's an actuator style box like the one shown in this thread for the analog system or if it's self contained in that digital controller that I have.

[fdryer]

My GM service manuals do not show a schematic for actuators. A basic diagram of a dc motor and pinouts. Below are snapshots for L200s hvac controls.