Should Numbers on Tekonsha Primus IQ Show Up When Trailer isn't Connected

Updated 09/03/2024 | Published 07/11/2019

Question:

I just had my 2012 Lexus GX in to have front/rear brakes replaced. I was thinking that prior to taking the car in, the Primus brake controller would display “a number” when he brake was applied...even when the trailer was NOT connected. When I picked my car up the display on the Primus shows two little dot lights on the bottom...but it does not display a number when applying the brakes trailer still not hooked up. I questioned the Lexus dealer about it, thinking they had done something to it...but of course they denied doing anything to it. My question is...should the display show a number when you apply the brakes even when disconnected from trailer? Thanks!

asked by: Scott S

Expert Reply:

The Tekonsha Primus IQ # TK90160 only shows a number on the display when the brakes are applied if a trailer is connected and the brakes are being applied. Without a trailer connected a number would not show up. You might try connecting to a trailer and you should see the numbers show up.

expert reply by: Jameson C

Kendle D.

9/2/2024

I am having essentially the same issue (2018 Subaru Outback) after having new brakes and rotors installed on all 4 wheels. I swear it used to display numbers when braking even without the trailer attached, but now it doesn't show them even with the trailer hooked up. I get the two little dots, and if I hit the blue button I get B1 and then can cycle through the boosts. I when I try to adjust the gain I see nothing, and I also no longer see the numbers fluctuate when braking with the trailer attached. If it helps, the brake lights are still working. So my questions are; this isn't right, right? And if it isn't, is it an issue I bring back to where the brakes were done, or an issue I bring back to the place that installed the braking controller? Thanks in advance for your help!

Jameson C.

9/3/2024

@KendleD What you see sounds normal. It should only show number changes on display if a trailer is hooked up. The only way it would do that without a trailer hooked up is if there was dirt or corrosion on the trailer connector that would trick it into thinking a trailer was connected.