Thanks, I checked page 3 and yes it does explain no motion activity etc but the led display on my unit has stayed lit for the past two days with no motion at all so I would say the unit may be faulty?, regards

mine goes off after a while.
are you sure it has been wired correctly?

frank

Road runner, the Tekonsha P3 will use almost no power when on standby, and incidentally this brake controller, to my knowledge anyway, is still produced in the US and is generally considered to be one of the best available. I certainly have had no issue with mine and I know of no acquaintances who have. You can find negative comments on almost anything you like to choose, my point being Tekonsha products are not Chinese rubbish.

Now, as noted the unit should turn itself off after about 15 mins......unless it senses that the vehicle is still powered up, something there is making your unit think it is still being used, following that 15 minute pause the unit will (should) go to sleep and should not awaken until you start up, put your foot on the brake pedal or touch any of the controls on the device, when it does awaken it should flash red at you telling you that there is no trailer connected (assuming no trailer is on at the time).

You say you are 'fairly confident' that the wiring is ok, my advice firstly is to ensure the wiring is ok, you may need to follow the path of each of the four wires connected to the control...be particularly sure that the input from the brake light circuit (red wire) is not energized unless the pedal is depressed, this is best checked with a multimeter to ensure not even a tiny current is detected, check also that the earth (white wire) is good, ideally it should go directly to the negative pole on your starter battery, again, use a multimeter to ensure continuity and satisfactory earthing. The main power supply to the controller (black wire) should be sourced directly from the positive post on the starter battery via a 30 amp fuse and via wire of correct gauge.

Finally check your trailer connection at the rear of your 'cruiser....follow the blue cable from the controller all the way to the trailer connection, check that there are no abrasion points along the route, does it come close to the exhaust for example, undo the plug, check closely that there are no errant strands of wire creating a minor connection between poles, check that there is nothing in there that could cause a cross connection, ie, moisture laden dust, insect hibernation etc.

If all these checks fail to find anything and the unit is still not shutting down I'm afraid there must be a fault....I do recall that I once came across another brand of brake controller that was faulty and had the experts stumped...turned out that the backyard installer had used screws that were too long to secure the unit to the bracket!

Naturally the supplier wasn't interested in replacing it under warranty.

Lets know how you go.

Thanks for showing interest in this and advice. I just disconnected each wire in turn and the red wire to the brake did nothing including the blue however disconnecting the white earth wire caused the display to flash non stop. Reconnected and flashing stopped. Disconnected the black wire  and no display. Reconnected all wires and display lights up but stays on. Next step is to check each wire and connection as per your suggestion. One thing I failed to mention is that the white earth wire is connected to the earth pole on one of the starter batteries but the black power wire is actually connected to the positive pole on the third accessory deep cycle battery so wondering if this could be a factor. The previous owner wired it up this way which I thougthougt was strange so will relocate the positive wire to see if that is the issue. Interestingly my neighbor had the previous model (voyager) on his Territory and the green led wouldnt go off yet I had the same model Voyager with no such problem so there you go. Will let you know the outcome of the black wire relocation,

Good one Frank, I forgot to mention that....you can get a 30 amp self-setting fuse from an auto parts store for maybe $20. Not sure if having the main power feed connected to an accessory battery is a good thing or not but for my money the starter or main battery will give uninterrupted supply.
The fact that the display flashed when you disconnected the earth is good, the P3 has several 'failure notifications' such as an ability to detect a short circuit, faulty electric brake magnets or, as you discovered, loss of an efficient earth to chassis.

ROAD RUNNER wrote:

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Well the great mystery has been solved thanks to some of your good advice peoples. Turns out that the round 7 pin plug on my towbar has 6 small LED lights above the plug that act as a test lamp and come on individually according to which wire has current flowing. The LEDs can be switched on and off by a small button on the plug body so when I pressed the button the brake controller display went off after the 15 mins period. Press it again and the display stays on due to live current connected to the brake controller blue wire. Thanks for everyones advice, regards RR

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I was getting ready to suggest that the car's computer may be testing the lamps on a periodic basis but I discounted this possibility when you said that disconnecting the red wire (brake lamp) made no difference. Now you are saying that the blue wire is responsible. I confess I don't understand how that could be possible since this is an output from the controller, not an input. Furthermore, it makes no sense to me why disconnecting the white wire (earth) does not interrupt power to the box.

Perhaps the lamp sense input is tied up to BAT+ via a pullup resistor. If so, then disconnecting the red wire would cause the sense input to sit at 12V, in which case the controller would think that the tow vehicle's brakes were applied. However, if this were the case, then the controller would energise the blue wire and the trailer brakes would be on all the time.

Normally, when the red wire is connected, the brake lamps provide a low resistance (10 ohms ?) path to ground, so the sense input would be sitting close to 0V. In retrospect, when testing for brake activity, the red wire should have been disconnected and held against ground for 15 minutes.

As for disconnecting the white wire, perhaps the box finds a return path via its metal frame, mounting screw, trailer chassis, tow ball, car chassis, and then on to the battery's negative terminal. The controller might sense the missing earth wire by monitoring the voltage across a low value sense resistor connected between the white wire and the metal frame.