Brake Controller and Brake Lights Not Working on 2007 Dodge Ram 2500 4wd Cummins Diesel

Question:

It is a 2007 Dodge Ram 2500 4WD Diesel. The problem is the Brake controller is not working no indicator light when brakes are depressed . I have no lights on trailer when the plug from trailer is put in. Actually I used a round test plug which is supposed to illuminate when turn signals , brakes or running lights are turned on .So there is something wrong. From what I have read some of these can be reset at a dealership. ? I had a 2003 that had a similar situation, I put a modulite 90901 ? on it and it corrected the problem. I am not sure if that will work on this.

asked by: Don H

Expert Reply:

It sounds like you have two unrelated issues going on. One is a brake controller that is not working. The second is lights not working on your trailer.

Let's start with your brake controller that “no longer lights up.” This is unlikely a result of a PCM setting. It sounds like you are not getting any power there. If you have a custom cable that plugs into your truck on one end, and plugs into your brake controller on the other, we can check your voltage there. Unplug the connector from the back of your brake controller. There will be four wires – we want to measure the voltage on the black wire using a voltage meter. (This is the 12-volt supply coming to the brake controller.) If you don't have a voltage meter you can order part # PT89ZR. If you do not have voltage at the connector then you will have to check the fuses and otherwise trace back the wiring checking for nicks or cuts.

If you do have voltage there then you may have a defective brake controller. You can further verify this by depressing the manual braking button on your controller and measuring for 12 volts on the blue wire. The voltage reading should go from 0 to just over 12 volts as you depress the manual brake override button/lever on the brake controller.

If you need a new brake controller I would recommend Tekonsha # TK90160 proportional brake controller. It will mount easy on your dash and with a custom connector for your Ram the installation will be a snap. The wiring connector is part # 3020-P. I have included a link to this product page and an installation video.

Regarding your trailer lights. That it is all of the lights not working you should be able to resolve this issue quickly. The most likely scenario is that the 7-pin connector on your truck is disconnected. Check under your truck jut behind where your 7-pin plug is and see if the connector back there has come off. Then, using a voltage meter check the pins on your tow vehicle's 7-pin connector. You should be able to see voltage on pins for blinkers, running lights, brake lights and so forth. I have attached a link showing trailer lighting and pin-outs for the connectors. Please measure the exact voltage on the brown wire for the running lights. Of course your truck lights should be turned on.

If the lighting circuits have voltage then that places the problem on the trailer side of the connection. I would expect for you to find a broken or corroded connection where the white wire from the wiring connector attaches to the trailer.

The easiest solution would be to have a friend with a 7-pin connector on their truck back up to your trailer and hook up. If you get lights then – the problem is on the truck side. If you still don't have lights – the problem is on the trailer side.

If none of these troubleshooting tips help resolve your issue, please contact me and we can go through further steps.