Any suggestions for a replacement motor?
The MMC had many supply issues after they ended the Smith's cabin heater system
(which are still available in either new whole systems or parts). According to the old parts books (with overlapping transition), the MMC fit one type from 1984 to 1987, then another 1987-1993, another 1993 to 1997, another type 1996-1997 and then another from 1998-2000. After that the systems (used also for AC) became the subject of many woeful discussions here and everywhere.
Moggers of post-2000 cars are beginning to remove these last systems, likely at the suggestion of predatory or poorly trained experts, (a sign over the door does not an expert make!) The latest systems might be poorly designed but THEY are curable at little cost. A properly trained and honest Aircon/heating person knows so. It is fascinating watching who does what. Removing entire heating system is very invasive and costly. Changing the pumping and components is cheap.
There is sadly no mention in these parts books of the supply system after the Smiths but I believe you may had a Galley heater. But that is no help as I am also told Galley do not answer request for parts.
All that being said, do not dismay. It is only the general design structure that can vary. The component parts of cabin climate systems is are largely generic and very cheap unless you buy them from the auto manufacturers that use them and supplied them for your car. You can easily find a buffet of fan motor replacement. At worst that will require an adapter plate you can fashion yourself with a drill and a bit of metal plate. For example, I have never had a problem with my trusty Smiths (though I have had two other MMC climate systems). However, I wanted more airflow. So I merely bought a stronger fan motor (25£) swapped it in and added a 4 identical position switch (off, speeds 1, 2, 3) (I use sturdy little metal toggle switches).
HOWEVER, all this is premature unless you want to save time. You may merely have a wiring problem, not unusual in a 28 year old system exposed to the elements. Once found, you can costlessly set it up so it will NEVER never occur again. If you want to upgrade performance, you can take the other route I am suggesting. I always think of such issues as the car's signal to me that it wants to be better. Amazing what that can produce over time.
As for a specific suggestion, work by dimensions with an eye on cfm. I will help if you publish the dimensions
gmg
