TR/512TR Blower Transistor Connector P/N?

Is it clips or screws holding this top cover on? I am terrified of breaking clips on this part since I havent removed it yet.

 

Inspected rheostat: its the new type without fuse despite my car being an ‘87. Must have been replaced in the past.

However, the new transistor did not solve the problem. Perhaps problem with rheostat? I will attempt to probe the connector which would plug into the transistor to see what is going on.

 

So upon further inspections its clear my car was wired for the 6-wire fan switch but has a 4-wire plugged in.

Perhaps this is why Im not getting anywhere? Could someone confirm if the 4-wire switch can be installed into the six-wire harness without any other modifications?


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Heres a relevant thread but the question remains unanswered, can old and new switches be interchanged (old switch in new harness AND new switch in old harness)?

https://www.ferrarichat.com/forum/threads/tr-junkies-an-oldie-but-a-goodie.162240/

 

Steve-

Firstly I cant thank you enough. Trouble shooting with you is a wonderful experience and I just hope I dont waste your time with silly responses to your to-the-point advice.

My switch definitely appears crossed as the wiring nor label matches the one previously pictured. However, the wiring does occupy the same connector pin positions. I cannot tell if the pin-outs are electrically the same without knowing more about the “correct” switch.

Please see attached pictures:
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Had a eureka moment!

Brought the fan control board to work to inspect with my electrical engineer. Everything probed out the way we expected it to.

Right before we were about to shrug our shoulders we noticed the browning below the four 10ohm resistors. This led us to inspect the resistors closer. Well wouldnt you know it- as a result of all of the heat/cold cycles one of the resistors leads had worked its way out of the solder joint. I touched up the solder joints and hope that this will resolves the problem.

All of these resistors are wired in series in the green wire circuit, when one was open then no current was moving through that part of the circuit at all.

I think its possible my stock transistor is still working. Hope so!


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Yup. Super simple. Id make a whole new board and parts before paying $400+ for some NOS one. So far my experience with the TR has been easy fixes solve most problems.

Keeping my fingers crosses that this is the solution.

 

It worked