Chrysler Repair: 98 Grand Voyager: no heat on driver side

Question
I just purchased a used 1998 Plymouth Grand Voyager and I love it even though it takes some getting use to the front wheel drive in the snow. I have a serious heating problem. The air conditioning is awesome on hot days but when its cold outside, I can only get heat coming out of the two front passenger vents. Someone told me to just duct tape non working vents so heat would eventually fill the van from the two working vents. Also, I have heard $300-700 from various mechanics because the dash may need to be detached but those estimates had me almost ready to buy a cigarette lighter portable heater for $40 until I found this website. Is it something that I can fix myself? Please help me because I really want to keep my family van. Thank you in advance.

Answer
Hi Scorpio,
The heater unit is complex: some of the parts can be serviced without removing the unit from the dash and some cannot. It also has a self-diagnostic capability which may identify exactly why there is no heat coming from the driver side vents (Is that basically what the problem is?)
I assume that when the blower is running that you do get air from the driver vents but the problem is that it is cold rather than warm air, correct?
If it is a problem that the air on the driver side is coming out but it is cold, then the likely problem is with the driver 'zone' blend air door actuator. The blend air actuator adjusts the path of the air going to a 'zone' by sending it either to the heater core or to the ac evaporator core or a variable mix of the two possibilities so as to get variable temperature choices. If the driver actuator was either defective or the door was binding up in the cold pathway direction then that could be the cause of the problem.
There are 6 buttons (with 5 of them having LED bulbs, the wash button doesn't have an LED) arranged around the lower left corner of the control panel. Please describe to me which of the LED bulbs are flashing when you first turn the key to the 'run' position. That would tell me about the 'status' of the unit as it stands now.
The unit can be calibrated and also can be tested to tell you what might be wrong with the situation. The best way for me to give you that information would be to copy about 5 pages from the manual and postal mail them to you as it is way too long for me to type it in here.
Once we get a handle on what is wrong I can then give you the info or more pages on how to correct what is wrong. If you would send me back some postal stamps to cover my copying and postage that would be nice, but not necessary to get this started.
So answer my questions and the LED bulb situation, and tell me your postal mailing address.
Please read the PS below and respond to it.
Thanks,
Roland