Schematics for the aerial relay, XJ Series III

Dear all,

Recently I had problems with the electrical aerial on my XJ Series III. One issue was the microswitch inside the aerial motor unit, another the green relay which controls the aerial movement. I believe it’s part no. DAC1820. In the end I had to replace two blown diodes in the relay circuit. In doing so, I decided to draw the circuit, which helped me to identify the culprits. It is a quite simple delay switch, in the heart of which is a relay (in the narrow sense of the word) on the one side and a capacitor on the other. If anyone is interested – or confronted with a similar issue, here’s the drawing:

Please be kind if there are any mistakes.

Speaking of which, the schematics given in the Haynes manual are at least misleading. They indicate that the relay (in the narrow sense) is powered by connections 3 and 2. However, the relay draws its current from connector 1 (+). 2 provides the ground (-). And connector 3 (from the radio) gives just a signal current to open the ground connection (2).

All best,
Florian

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