Have been having an overheating problem on the main circuit board in my current ACC box (pushbutton). The heating seems to be concentrated near the relay located in the middle of the three toward the rear of the board. At this point I have not been able to decide which high current device this particular relay supplies.

Have disconnected the monovalve, the aux water pump, and the A/C compressor. This seriously limits the answer to the heater fan, but it runs quite well when hooked directly to +/- 12v. Sooo, has anyone figured out what each of the relays is hooked to, and is there any high current device in the the other (temperature) control box behind the glove box? Have not had it opened or even out of its normal location.

Thanks in advance for any ideas.

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1961 190Db retired
1968 220D/8 325,000
1983 300D 164,150