Another HVAC ??? (archive)

OK Group, here is today's HVAC question!
I replaced the blower motor in my '86 735 last year with a used motor and all went well. I had previously replaced the controls and PB module with Programa units as I was having some trouble with the 'flickering LED's'. System worked OK.
Checked all vacuum hoses and connections and made a few minor repairs at that time.
Just last week my wife said she had no heat. After checking all controls seemed OK but the blower was not on.
I pulled the cowl cover to check incoming voltage and in the defrost mode I had full battery voltage of 13.8v to the incoming motor leads but when I plugged them back into the motor terminals the motor only ran slow.
Now to the dilema! I used a pair of jumper leads to connect direct battery voltage to the motor and it runs full speed just fine. I have tried this a number of times and the blower always works, so I would have to rule out that sytem component.
Only when I hook the control leads back up will it not run at full speed even though I read full voltage incoming.

Anyone have any insight??
Another question......What are the purpose of the transistor packs(or whatevere they are) that are mounted to the left and right blower housing cover over the impeller area??
They sure have a lot of wires running to them, they must hae some purpose I am not aware of.
Thanks in advance, as usual, for all replies.

Tom Marino in PA

Follow Ups:

"Tom" Jens 17:53 1/21/2001 (1)
- Re: "Tom" Tom M. 22:39 1/21/2001 (0)
Re: Another HVAC ??? Callan 13:24 1/21/2001 (1)
- Re: Another HVAC ??? Tom M. 16:56 1/21/2001 (0)
PS Jens 13:19 1/21/2001 (0)
Re: Another HVAC ??? Jens 13:17 1/21/2001 (0)

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