my 85 300sd is really confusing me. here is the problem.

When i first start the car the blower motor for the ac/heat will not come on, but i9f i turn the key back just a tiny bit the blower comes on and works great. But the transmission does not shift when the blower motor is going. So no heat. i have taken the dash center console apart check all around the hood i do not see a vacuum line broken or disconnected anywhere. Any ideas?????

 

If manipulating the Key allows the Blower to work I would suspect something is not right with the Ignition Switch or the parts of the steering lock that are between the Lock Tumbler the Key goes into and the Ignition Switch itself.

I do not know how that would be related to your Transmission (I assume it is an Automatic Transmission that needs Vacuum).
However, there is a Vacuum Shutoff Valve located on the Steering Colum Lock that is actuated when you turn your Key. That Valve sends or cuts off the Vacuum to the Vacuum Shutoff Valve on the Fuel Injection Pump.

I am supposing that if the Vacuum Valve on the Steering Colum was not working right or the Cam Mechanism that operates it when you turn the Key is not working right it could be bleeding off the Vacuum. But, that is just a guess.

To see if it the Transmission is getting enough Vacuum T a Vacuum Gauge in to the upper most Vacuum Hose Connection on the Vacuum Control Valve or T in down at the Vacuum Modulator on the side of the Transmission.

I do not know enough about an 85 300SD to know if there is anything electrical that could cause your trans not to shift.