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1990 Allante
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Discussion Starter #1
I see a lot of posts about the heater fan staying on (when car shut off) or no fan at all. Mine wouldn't work at all. I isolated it to the control unit on the top forward firewall. After looking at the schematic, I decided the only part in there was a transformer. The problem is a classic failed (overloaded) transistor. I got the part # off the unit and started looking. The only source for the transistor was ebay at $50. $50 or $130 for a new
unit?? Well I know transistor are a lot cheaper than $50 so I took it to my avionics guy (I'm an aircraft mechanic) and he matched it to 2 part numbers for transistors rated at 15amps. These are PNP...most transistors are NPNs (easier to get). I used a 2N5876 (free, $16 on Ebay) and bought 2 NTE219) for back-ups on ebay for $11 for 2. The transistor is soldiered in and the screw heads are covered with plastic. You have to cut the plastic carefully and not mess up the circuitboard. I drilled the screws off, unsoldered the 2 pins, used 2 small bolts and nuts to attach the transistor and soldered one screw and pins. I covered the exposed area with a thin coat of silicone. I'd post a picture, but it's in my car working fine...now the radio!
 
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