Deep engine stumble when heater blower turned on?

It sounds like your blower motor is starting to short out, to be sure let's unplug the blower motor to see if the problem still occurs. Here is the location of the blower motor and how to change it out in case you need it. Check out the images (below). Please let us know what happens.

Hi Ken,
As always much appreciated for your confirmation. About what I suspected but never experienced this problem in my 55 years of driving until now. Thank you!

Yep, that is a good one all right, please let me know how it goes.

Will do! Got this page bookmarked for near future feedback. Best regards.

Hi Ken,

It took a while for me to get around to this problem. So, the shop informed me that I have a seized A/C compressor. To fix this problem they said it will cost me $1,800.00. Does this price sound right to you?

it sounds a little high, here is the estimate from the book:

Compressor With Clutch Assembly 1.8 HRS @ shop rate

Compressor 883204208084 $585.78 new (you can find cheaper ones on amazon)

Here is one for $362.00 which included the new compressor and the condenser with oil and O rings:

https://amzn.to/40VXI7G

Here is a guide to help you with the vacuum down and recharge which should run about 1.0 hrs of labor plus refrigerant:

https://www.2carpros.com/articles/re-charge-an-air-conditioner-system

Check out the images (below). Please let us know what happens.

Thanks Ken, as always your generous info very helpful!
Best regards, Peter

Good to hear, please use 2CarPros anytime we are here to help.