Lumen SST-4000G trailer lights ECU and wiring loom

Submitted: Saturday, May 04, 2019 at 11:58
ThreadID: 138272 Views:13838 Replies:2 FollowUps:1
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Hi Everyone, I've just fitted up a tow bar to the wifes 2017 Mazda CX3 that I got from the wreckers. It came with the above wiring kit which had what looked liked "piggy back" type connections to each tail light assembly, an earth wire and a red wire to/from the ECU.(Electronic control unit)
So I guess the Question is, does the ECU need to have its own power in and would this be the red wire?
It seems logical because the ECU wouldn't want to rely on the power from the tail lights etc, especially the blinkers! Thanks.
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Reply By: Ron N - Saturday, May 04, 2019 at 12:49

Saturday, May 04, 2019 at 12:49
Gerry, on another forum, a bloke put some photos up (links below), that indicate the ECU needs a separate 12V input.

However, he doesn't provide a wire colour or wiring diagram, but he does show an itemised photo of the ECU plug.

Lumen ECU

Lumen ECU plug

Cheers, Ron.
AnswerID: 625352

Reply By: RMD - Saturday, May 04, 2019 at 12:51

Saturday, May 04, 2019 at 12:51
My guess is that seeing the Mazda has a CANBUS system the wiring can’t directly connect to the vehicle loom. Any connection is likely to be only sensing wiring and that red main feed, supplies the power for the towbar ECU/Controller to provide the actual power for any trailer related lighting through heavier wires direct from the controller to the towbar plug.
AnswerID: 625353

Follow Up By: GerryG - Saturday, May 04, 2019 at 16:26

Saturday, May 04, 2019 at 16:26
As you suggested, RMD these new vehicles aren't as easy to play with electrically with all the modern electronics.
Anyway, I've got trailer lights which is all that matters.
So thanks Ron and RMD.
FollowupID: 898988

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