Has anyone had any luck getting these reconditioned or repaired (or finding an alternate source)? My temp control rheostat sends 4v to my heater monovalve regardless of where I turn the dial. No wonder the a/c was not as good as it could be. While I can temporarily send 12v to close the valve, in the long term a rheostat fix is in order. Alas, the pair (temp and fan) if still available in the yellow boxes are about $1500(!)
I assume there is another application for them but that does not mean it will make them easier or less costly to get. The fan speed controller has been expensive and difficult or impossible to get for some time. I would have thought if there was an alternate source it would have been exploited by now and I have not heard of that happening. I have never seen a failure of the temp control so have no experience in that matter.
Not following this as the temp control rheostat does not control the heater monovalve directly. The temp control rheostat sends a signal to the AC ECU that then runs the heater monovalve by PWMing the ground side connection of the coil to be ground (which puts +12V across the coil and closes the valve) or open (which puts 0V across the coil and opens the valve). Are you saying that you have made the resistance measurement (at the unplugged AC ECU connector IIRC) described in Section H of the TR WSM and the temp control rheostat fails that resistance test?
Good day RifleDriver, Do you have or know where I could located a dead or failed controller? I ask, as depending upon its design, etc I could design and manufacture a replacement for a whole less than what has been quoted. Cheers, Sam
No I do not. It has been some time since I have replaced one. There are several part numbers and 2 different designs. Several supersede to 140151 which is NLA. The earlier design has a different connector and I have no idea if beyond that they are interchangeable. I do have a new spare 140151 for my own car. I could be talked into loaning it to you.
I believe the monovalve water heater valve works on: open all the time until grounded? The fan speed controller? Is there a way to control the blower speed motor with different values of resistors and a 4 speed switch? I know this would not keep the TR completely original. But could it not be reworked so it is simple like the older cars. Instead of climate temp control. Turn the heat on or off or turn the A/C on or off? I did that in one of my hot rods. I installed a A/C compressor cut out switch as described in one of the older Prancing horse magazines. Throw the compressor off and you get just fresh air.
After taking a look at the parts book just now it looks like the A/C temp control is a simple pot. You know how the pictures can be and my memory of that part is really non existent because as I said it has never been an issue. I agree with Steve though, the control signal is not a straight shot to the heater valve.
Good day Brian, Understood and thanks for the offer! For now...perhaps when you have some spare time could you e-mail me some pictures of your spare and in particular the electrical/electronic areas? The pics will give me an overview of what the controller looks like. Given some of the Ferrari controllers I have seen I am quite confident that something could be remade that is a lot less expensive and more importantly available. I say this, as I do these types of projects regularly for my work (which is mostly Commercial and Industrial HVAC and controls) and so I am quite familiar with the process. Cheers, Sam
There is actually a picture of it on Ricambi's web site here 140151 SWITCH/A/C - Ricambi America, Inc. Click on the picture to get a blow up. Not sure you will be able to get better than that but let me know.
No, I have not. I have not appreciated that the temp control rheostat sends a message to an ECU, which makes a calculation before sending a specific amount of voltage to the heater valve. I will run that resistance test this weekend. As for the fan speed rheostat, from more reading on Fchat I suspect I have the common power transistor problem, which may be easy to repair.
Yes, if full speed works, but no lower speed works = very strong sign that it's a bad power transistor.
Good day Brian, Thanks for the link to the picture! This is all I need for now, thank you! I would say that there is a very high probability that this item could be easily redesigned and offered for sale for significantly less than price mentioned in this thread. If anyone has a dead one, etc contact me, as I am certain I can do something. Cheers, Sam Image Unavailable, Please Login
