Brake Lamps and Brake Controller on 2008 Dodge Ram Not Working Wtih Brake Pedal

Updated 05/06/2021 | Published 05/05/2021

Question:

2008 Dodge Ram with a break control switch. We picked up our newer travel trailer recently. Noticed that all lighting on both truck and our trailer worked, except the break lights. All 3 break lights are out on the ram and I could not adjust the control switch for breaking, but green light was on indicating trailer is connected. Could adjust the control switch enough to get red light and break with the manual switch. Disconnected the trailer and all 3 break lights still out. Checked the fuses located under the hood. All appear to be fine. We noticed when we started the truck without turning the head lights on, that within a minute or two, the tail lights came on and remained on. Shut off the truck and a minute or so later, the tail lights shut off. I think the fuse box is intergrated in the location under the hood. Some web sites indicate there are two. If so, it must be a well kept secret. Can not find anything in the cab. Read that if you can not adjust control switch, it is not getting power from breaks. I do not want to change parts until I find something that fixes the issue. Help! Thank you

asked by: Brian K

Expert Reply:

By 'Brake Control Switch', I'm assuming you're speaking of a brake controller.

The symptoms you describe seem to point to a blown CHMSL fuse, which is a 20A fuse located in the engine compartment fuse box in location # 26. This fuse controls the brake switch, the Center High Mounted Stop Lamp (3rd brake lamp) and stop lamp switch. If the fuse or the stop lamp switch was bad, it would certainly explain what you have going on.

expert reply by: Mike L