jhowland Report post Posted November 9, 2021 (edited) found out I have no brake lights, both are out. Fuse is good, and I put in a brand new relay. Still no joy. I also noted that stepping on the brake does NOT deactivate cruise control. I was troubleshooting more today and when I stepped on brake the lights came on, as they should. But only once. I suspect one or both of the switches on the air brake need to be replaced. Looks like a very simple fix but does anyone have part numbers or another idea? Thanks 04 40DST diplomat le Edited November 9, 2021 by jhowland forgot info Share this post Link to post Share on other sites
richard5933 Report post Posted November 10, 2021 Not sure about yours in particular, but this should be a NAPA item (assuming you have a NAPA that carries truck parts). To confirm, are there any numbers on the one you've got now? They are just basic pneumatically operated on/off switches. Share this post Link to post Share on other sites
rayin Report post Posted November 11, 2021 Your switches, connections and grounds might just need a good cleaning, it costs nothing but time and effort. My water heater would not stay lit yesterday, I unplugged and reattached the flame sensor wire on the control board and the WH began working fine. Share this post Link to post Share on other sites
kaypsmith Report post Posted November 11, 2021 When was the last time you purged the air tanks on the coach? Share this post Link to post Share on other sites
