I had some problems with the speed controller/ECU and didn't find any auto mode. The ECU just sends an DC signal to the controller and that's it. You have to be mindful when changing the transistors that the Hfe is the same. I first put in transistors with a higher current rate ( better) but higher Hfe and the control was out of balance. At the end i changed them again with 2 new Tip142 and works perfect. Correction : Now that i remember there is an overheat protection for the transistors. The little NTC glued between the 2 transistors. But no HVAC regulation.
Because the car is a Challenge car and was raced, the AC itself is gone. Compressor and condensor and associated parts long ago removed. All I really need is the fan and heater working. Interestingly, when I started looking around at it this morning, the fan turned off, then started turning on and off on its own intermittantly. What do you guys think that is indicative of?
Also, as the car is new to me, whats the best way to remove the carpet and panels around the HVAC unit under the bonnet? Sorry for such a basic question, but figured there may be a tried methods rather than reinventing the wheel. Thanks!
Assuming the 348 is the same as the F355... Remove the rubber seal on 3 sides of the luggage compartment (you can leave the bonnet (trunk) hinge side on). Remove the 4 screws around the air inlet (put them somewhere safe, don't let them fall into the airbox side channels). Remove the metal bumper strip which goes around the luggage area (several countersunk screws). Remove the fusebox and CD stacker covers to access the nuts and bolts holding the large liner piece to the smaller side pieces (can be tricky). It may be necessary to unscrew the liner side pieces, too, for more manoeuverability. The liners are fragile.. especially the pointy bits around the bonnect hinges. You may need some rubberized superglue if you crack them. Reassembly can be a bit of a juggling act, lining up the screw holes, getting the pieces to overlap correctly, not dropping the bolts, etc.
[QUOTE="Jasonberkeley, post: 145865624, member: 207415"...the fan turned off, then started turning on and off on its own intermittantly. What do you guys think that is indicative of?[/QUOTE] This is exactly how the blower controls fail in the 348 when the control module regulators, the power transistors (TIP142), fail. I believe these generally fail shorted, which would most likely make the fan blow full blast. The good news is that these are easy to replace.
Thanks for all the feedback guys. Having a tough time finding a new power module with the fan speed controller. I hate electrical stuff and am not very good at it. Does anyone know of a source for a replacement or someone who repairs these? Havent gotten it apart yet- new puppy keeping us busy and on our toes, and garage is freezing. Doesnt feel much like spring here in NW CT. New garage addition with heat should be finished just in time for warm weather! Hopefully this weekend I can get it apart. Or at least start... I did find a new micro relay which ill try just in case that's it, though it sounds like that's a long shot.
Seems that the fan power module (speed controller) is not available new anymore and even used ones are hard to find. However, your power module might be good. Before you suspect the module, you need to get access to it and disconnect the small plug (as advised in earlier posts). Then see what happens with the blower fan and let us know.
Mine does this too. My issue is the wiring harness connection to the back of the climate controls. People discuss using stabilant 22a to fix the problem. When open up the control and detach and reattach the wiring harness probloem goes away for a few trips.
