Redarc Tow Pro problem

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Originally Posted by LandyAndy

....There is no brake light activation with manually operated electric trailer brakes,the brake light only comes from the brake pedal....

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Andrew, the TowPro does activate the trailer brake light when manually operated if the diode is ftted upstream of the splice (CJB side of splice).
This was documented in the D3 thread on page 2, so easily missed if reading only D4 thread:
http://www.aulro.com/afvb/d3-d4-rrs/...d-photo-2.html
See posts 11 (by amaruskanic) and 12 (by sniegy).

The diode needs to be upstream (CJB side) of the splice so that the TowPro manual override button illuminates the trailer brake lights.
The sketch below is for a D3 from the same thread and so the wire colour is different for the D4. (D3 green/purple = D4 red).

This arrangement will only turn on the trailer brake lights when the manual button is pressed. The vehicle lights operate based on the signal from brake light switch.

If the diode is not located upstream of the splice, the trailer lights will not illuminate when you press the manual button but the TowPro will still work.
http://www.aulro.com/afvb/members/lr...diode-0002.jpg




This is why I wondered if John's (OP) diode was perhaps fitted backwards or in the wrong location, affecting his signal to TowPro.
But he's confirmed it was already fitted with his original EBC, so shouldn't be causing his current issue.

Cheers,
Scott

Having a think again about what I have done and the LED indications, then re-reading the active calibration, I think Rob may be on the right track. I had the Tow Pro installed for a few days and driving around BUT I don't think I have done enough of the "up to 20" braking applications. I'll drive around a bit more and then reconnect the van and see if there is any change.

Again thanks every who has given hints and tips on this issue.

Cheers and Merry Christmas

John

Quote:

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Originally Posted by Kalbee118

I have 0.01V on the RED brake light wire AFTER the diode I installed! I have 0.0V on the original brake light wire in the vehicle. Have I used to big a diode to cause this problem?

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The 0.01V will be coming from the Tow-Pro. Being 0V on the vehicle side shows that the diode is working correctly.

Quote:

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Originally Posted by LRD414

The diode needs to be upstream (CJB side) of the splice so that the TowPro manual override button illuminates the trailer brake lights.

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In this configuration the diode must be capable of handling the current draw of all stop lights including handling the generated heat if the stop lights are incandescent or fitted with load resistors and are on for an extended time.

Sniegy advised 3A diode.

If that was just for the sense wire for the controller that couldn't feed back to operate trailer stop lights then that is more than adequate. However 2 x 21W globes is 3.5A @ 12V, let alone 4 if fitted.