Older Generation Primus Cequent Brake Controller User Manual

Updated 11/01/2024 | Published 09/04/2014

Question:

I just bought a 2008 GMC Serria 1500 and it has a Primus Cequent brake controller in it. This is not the Primus controller with a boost setting button on top but it has a flipper switch on the right side. Where can I find a user manual for it or how does it work for setting the booster? All I can find is the user manual for the one with the boost button on the top side. Any help is appreciated.

asked by: Mark

Expert Reply:

I was able to find the older style Primus Brake Controller part number 39515 installation instructions and I attached the picture to the right for you to check out.

The flipper switch on the side of the controller does control the aggressiveness of the brake application. With the lever flipped back away from the front of the controller the braking will be delayed, straight down will be normal, and towards the front is aggressive.

expert reply by: Jameson C

click to enlarge

Ed O.

10/21/2024

Jameson, Your response to a previous customer is probably the same information I'm looking for, i. e., "the older style Primus Brake Controller part number 39515 installation instructions". The Primus I have was purchased about year 2000. If you can send me the installation instructions, I will be most appreciative. I especially need wiring instructions to wire the controller to a 1997 Chevrolet K3500 crewcab pickup truck. My controller has a blue sticker marked "CEQUENT #P000153778. I will be using it with two and three axle trailers. Thank you very much.

Kevin C.

11/1/2024

@EdO The instructions are simply just what's pictured above but I can send you a link to a clearer version of them so you can at least read them. There really isn't any wiring instructions but like all universal splice-in harnesses you should have a blue, white, black, and red wire to connect in the following manner: White - ground to frame Blue - run to brake controller output pin in 7-way Black - run to battery with 30 amp inline circuit breaker # PK54530 Red - run to cold side of the brake light switch To find the cold side of the brake light switch you'll need to test the wires coming off of the brake pedal for the one wire that only has power when the brake pedal is being depressed. If you can't find it or the wire gauge is too thin to splice into you can use a universal stop light switch # RM-751000 and connect its output to the red wire from the Primus wire harness.