After several hours of work , my mech extracted the fans.
I managed to replace the Darlingtons yesterday night. They where both open in one junction. Could not test the other components as I did not managed to remove the heat sink . Tomorrow the mech will put the fans again on board. I hope the repair succeeded and I will have again the mid and low speed as in the garage had already put 4 hours of work on the bill…
You might want to replace the ‘crappy-BLUE-Hella relays’ if they are fitted.
86-178A Inoperative Blue Relay.pdf (79.8 KB)
I think there are TWO relays in the fan assys.
One for the fan power and one to ‘short’ across the Darlington Emitter/Collector on HIGH.
If they are Blue Hella, you might at least take them apart and check the contacts?
Andreal …
With the symptoms you described and the success rate of replacing the Darlington transistors I’d be shocked if your repair doesn’t work … shocked I say !
Over the years I had the same problem with both my fans and simply replacing the Darlington repaired them. Actually I had ALL the other electronic bits on hand but decided in the end to only replace the Darlingtons (sometimes it’s better to leave well enough alone). That was many years ago and the fans are still going strong.
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AFAIK the relays inside the blower housings are Hella brand but aren’t the same relays as on the firewall, they are a type with the internal diode. When I replaced mine, (possibly unnecessarily) I used a standard aftermarket (sealed) diode and soldered an external diode to the pins.
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The first blower have been remounted and it work at medium and low speed… i hope the other will work too !
the next phase is trying to make the AC working again. Now the situation is that the car have still R12 valves but there isn’t’ enought gas to even start the compressor.
How can i test if the compressor is still working before even attempting to convert the system to another gas?
Place a ‘jumper-wire’ in place of the relay 30/87 (or 3/5) terminals and the compressor clutch should become energized.
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