Mpace6b

1985 300D automatic trans om617.952 and automatic climate control.

Basically, with key in the run position the blower motor comes on and climate control works other than some vacuum issues with the dash pods and blend doors, but the transmission will not shift normally, it will go to redline in every gear. If i turn the ignition switch backwards until the climate control shuts off, then it shifts fine. But they will not both function at the same time.

Transmission seems like it forgets how/when to shift when the climate control has power sent to it. Ive replaced the electrical portion of the ignition switch because i assumed it was a culprit and upon visual inspection some of the contacts were just totally fried so i replaced it anyway.

So my question is is there some electrical components i need to chase down? Or are the HVAC leaks probaby robbing all the vacuum from the modulator? I have scoured the internet for anything relatable and only find the normal "how to troubleshoot vacuum leaks, how to adjust/tune transmission". Just looking for how to proceed.

alexanderfoti

I would say you are on the right track with this!