Primus Brake Controller Side Lever Adjustment and Light Staying On All of the Time  

Question:

Expert Reply:

It sounds as if you have a Tekonsha Primus brake controller without the boost function built in. Your controller should have a power adjustment wheel on the left side and a manual brake activation slide switch on the right side. If there is a lever on the side it is most likely a leveling lever that needs to be set so that the sensor in the controller is level and will supply the proper voltage with deceleration of the vehicle.

The lever for leveling the brake controller is normally pointed on one end or has an arrow on it, that is designed to be pointed straight down at the ground, when the vehicle is level. This allows for installation of the brake controller at varying angles in the towing vehicle. You may find that pointing the lever in the correct position allows the brake controller to go into power saving mode. If you are leaving the trailer connected to the vehicle the brake controller will not go into power saving mode because it detects a complete circuit and remains ready to operate when needed.

Other than the lever mentioned above, the installation and setup of your controller should be the same as the installation and adjustment for the Tekonsha PRIMUS IQ , item # TK90160, which I have linked instructions to. At this time we do not have instructions available for the older models of the Primus controller.

The display on a brake controller is designed to be used for thousands of hours and typically does not burn out. The amperage draw for the display is so small, as little as 3 miliamps, that the battery will actually discharge faster while sitting than the brake controller can cause it to discharge so, unless your tow vehicle sits for extremely extended periods of time, you will not need to worry about disconnecting the controller, unless you feel the need to. Some older controllers did not have a power saving mode built in.

expert reply by: Robert G

0

John

6/2/2011

It sounds as if you have a Tekonsha Primus brake controller without the boost function built in. Your controller should have a power adjustment wheel on the left side and a manual brake activation slide switch on the right side. If there is a lever on the side it is most likely a leveling lever that needs to be set so that the sensor in the controller is level and will supply the proper voltage with deceleration of the vehicle. The lever for leveling the brake controller is normally pointed on one end or has an arrow on it, that is designed to be pointed straight down at the ground, when the vehicle is level. This allows for installation of the brake controller at varying angles in the towing vehicle. You may find that pointing the lever in the correct position allows the brake controller to go into power saving mode. If you are leaving the trailer connected to the vehicle the brake controller will not go into power saving mode because it detects a complete circuit and remains ready to operate when needed. Other than the lever mentioned above, the installation and setup of your controller should be the same as the installation and adjustment for the Tekonsha PRIMUS IQ , item # TK90160, which I have linked instructions to. At this time we do not have instructions available for the older models of the Primus controller. The display on a brake controller is designed to be used for thousands of hours and typically does not burn out. The amperage draw for the display is so small, as little as 3 miliamps, that the battery will actually discharge faster while sitting than the brake controller can cause it to discharge so, unless your tow vehicle sits for extremely extended periods of time, you will not need to worry about disconnecting the controller, unless you feel the need to. Some older controllers did not have a power saving mode built in.

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Bob G.

6/2/2011

For your 7 volt reading, there are several things to check. First, I would check the output on the Blue wire at the back of the controller with a multimeter, item # BTMT15 if needed. With the manual lever activated fully and the blue wire severed, about 6 inches away from the controller, you should get full power at the blue wire, if not, you should check the power input on the black wire. If the black wire does not have 12-13 volts then you need to evaluate the connection to power or change the connection to directly to the battery 12 volt positive post. If the black wire has 12-13 volts and the blue wire does not your controller most likely has an internal issue that is not sending the full signal out on the output wire and will need to be replaced, if braking performance is less than desired. Next, if the output on the blue wire shows 12-13 volts with the wire severed and the manual slide activated fully, then your attention will need to turn to the trailer connector at the back of the vehicle. After reconnecting the blue wire, check the connector for corrosion inside, front and back. Corrosion in the connector can limit the amount of power the brake magnets are able to draw on the system and cause a low voltage reading at the controller. If the vehicle side connector is fine check the trailer side connector. If the trailer side connector is fine check the ground connection at the trailer tongue and the ground connections for the trailer brake magnets. Next, check any splices in the wring on the trailer related to the brake magnets. If you do not find any problem up to this point, you will need to check the trailer brake magnets for proper function. We have put together and article on testing brake magnets, see link, that details several tests, start with the first test and proceed through the tests, until you find an issue or eliminate all of the trailer brake magnets as the problem. One of these tests should locate the source of the reduced voltage, it just takes a bit of persistence to determine where the problem lies.

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