I removed the rear blower but would really like to be able to turn on the front blowers go get more heat sometimes. They are set up so if you turn up the temperature control, they are shut off. I made some measurements of the controller and found that the internal micro disables the fans if the temperature control voltage is more than 0 volts.

Has anyone found a way around this. I would love to re-engineer this mess.

By the way, the driver amplifiers are available in China at the semiconductor markets. If you have a friend there, they cost only a few dollars each. The part is Infineon (formerly Siemens) TCA2465.

 

You may want to speak to Loren. He rebuilds the CCUs and knows them very well. He rebuild one of my CCUs and it works great. (No affiliations).

http://www.systemsc.com/index.html