tmiles2246 Posted March 17, 2008 Report Share Posted March 17, 2008 I know this is off the subject of radio install, though I'm thinking someone might have the answer. I'm trying to hardwire a brake controller for electric brakes to tow a camper on my 04 Cadillac SRX V6 AWD vehicle. I have the 4-wire and modular working now and will install the 7-wire plug as well. The "trained technician" camper installer can't find the vehicle brake (constant) power wire that runs to the brake controller to inform the controller the brakes are being applied. In most vehicles, the wire is off the brake pedal. Not sure if this is the case with this vehicle. The Cadillac Escallade brake power wire is located under the master brake cylinder somewhere. Quote Link to post Share on other sites
shotgun_customs Posted March 17, 2008 Report Share Posted March 17, 2008 The SRX uses a 5V reference signal for the brake switch. A switch can be installed to trigger a relay that would inturn provide the brake signal needed for the brake controler. I'm sure I could get your SRX ready for towing if you would like to make a trip to Raleigh/Cary. The Escalade's are much easier b/c they are prewire for the brake controller. The 06's and older come w/ a harness that wires to the controller and then plugs into the convenience center. The 07's and newer have all the wires taped to a harness behind the knee bolster. All years will need fuse/s installed in the fuse box under the hood. And the 07's and newer have two wires w/ ring terminals that need to be connected to studs in that same fuse box. Quote Link to post Share on other sites
tmiles2246 Posted March 17, 2008 Author Report Share Posted March 17, 2008 I'm just down the road from you to the south. How would the switch to the relay work? Would I have to flip the switch to activate the brakes each time or is the switch working on it's own? The vehicle is wired with 10/2 gauge wire from the battery to the back of the vehicle with two relays under the hood. One wire off one relay goes to the rear 7-way plug and the other wire off the other relay goes inside the drivers side cabin for the controller. The 7-pin plug is mounted and wired to the lights in the back of the vehicle. I don't have the controller yet. The installer had everything done except finding the constant brake wire for the controller. The biggest concern was tapping into the wrong wire and popping all the air bags. One suggestion was to run the brake signal off the rear brake light wire back to the brake controller; not sure if that would work or not. I'm waiting for Raleigh hitches to call back with news as to whether they can do the job or not. If they can, it will be tomorrow. You sound like you might be able to finish the job. What's your schedule looking like? Quote Link to post Share on other sites
shotgun_customs Posted March 17, 2008 Report Share Posted March 17, 2008 The controller is looking for a 12v signal that drops to grd when the pedal is pressed. I could install a switch that is engaged when the brake is applied. This switch would trigger a relay. The "normally closed" connection, 87a-30, would be 12v and the "normally open" connection, 87-30, would be to grd. The down side to this would be an audible click when the relay engages, every press of the brake. I could also run a wire from the taillamp, but would probably need to convert that signal w/ a relay as well. But this would be in the rear behind panels and may not be as noticeable. I'm sure I could get it to work either way. I assume u just want it to work and be reliable, and not so concerned how it works. Correct? You can contact me privatly for info. I manage the accessory dept for a large well known dealership and don't want other to think I'm tring to advertise on this forum. Quote Link to post Share on other sites
tmiles2246 Posted March 19, 2008 Author Report Share Posted March 19, 2008 Thank-you shotgun customs for getting my family and I on the road with electric brakes for our trailer, when no one else in this region had a clue as to stepping up the voltage. The relay switch you installed is amazing and working better than I had imagined. The brake controller is getting the proper 12v signal through the switch and allowing for safer travel. I'll be looking you up in the future for any installation concerns I may have for my next Z series radio, as well. Quote Link to post Share on other sites
iiibdsiil Posted March 23, 2008 Report Share Posted March 23, 2008 Hey, Pinehurst! My folks have a place in Southern Pines. Sorry for the interrupt. Quote Link to post Share on other sites
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