Right blower motor blows hi speed only all the time. Only way to shut it off is to pull the fuse. Looking for answers, Dale
Most likely the transistor is shorted closed. The circuit board cars have power all of the time and the running speeds are controlled by the transistor. It is on the circuit board as in Kirbys book illustration.
Thank you Dick. That was my guess but I am glad to have another opinion. I was hoping not to have to remove the blower but I will do what is needed. It all occured when I disconnected the battery to replace another part on the car and as soon as I connected the negative terminal the blower started running. Somehow it got shorted out in the process. Again many thanks. Dale
There is also a crappy blue Hella relay in the blower assy that ‘shorts’ across the output transistor when HIGH is selected to save the transistor from having to pass that current through.
The relays are known to have issues and recommended to replace them in many circuits.
86-178A Inoperative Blue Relay.pdf (79.8 KB)
Thank you for the info. I will definitely keep that in mind as I tackle this project. Dale