Technician Talk

2005 Chrysler 300C 5.7L Hemi Brake Light problem

  • Hello I own above car-47500 miles. My Brake lights and center lamp dont light up,when brakes applied. My manual shows a 20 amp fuse in Cavity 15,however there is no bottom contact for fuse,and no fuse was there when I opened rear fuse panel in trunk. The 10 amp was good in cavity 19. There are 2 rows of relays at far right and bottom, 25,45,46 are used-but not listed in owners manual.The other 3 are not used. I replaced relay in 45,as that was shown on a diagram I found online as the stop lamp inhibit relay,and it was said the failure of this relay would cause this problem.However,when I replaced that relay,it made no difference. I contacted Chrysler dealership,they told me "our software tell us only that a relay goes in the slot,but not what the relay is for.How can that be so? They said only thing to do is make appt for it to be hooked to their diagnostic equip next Monday. Mech I took it to at first said fuses were good,bulb filiaments look good thru lense,and suggested trying brake switch. I called dealership first. Can you provide me with any assistance?   Thank you in advance!

  • Hello.

    Our wiring diagram shows that fuse 15 is used only with the optional trailer towing package so that’s probably why there’s no fuse there.

    Did you determine fuse 19 was good by its appearance? You can't always tell by looking at it. Test for continuity or replace it with a known good fuse.

    If all relays and fuses are good, I’d look at the brake light switch. That’s the next logical step.


  • Hello, thank you very much for your information about fuse 15-owners manual mentions nothing about trailer pkge. Do you know which relay is "stop lamp inhibit relay"? This is suppose to control all 3 brakes lights in certain situations(ABS possibly) Some of the diagrams I've seen on net show this relay in front-some in rear panel. Do you have any links to accurate diagrams? I did look at fuse 19,I bought some spares,and will replace the fuse in panel with new one and test. I would like to find this stop lamp inhibit relay and replace it,before I get new brake  switch installed. Do you know if there is a good quality relay tester available to the public? Thank you very much for all your help!!!!

  • Hi there!

    There are two diagrams relating to the stop lamp inhibit relay in ChiltonDIY, to view them in your subscription, follow this path from the navigation outline:

    Wiring < Lighting < Exterior Lights < Rear Lighting

    If you haven't already, subscribe to the information for the 2005 Chrysler 300C at ChiltonDIY to view the diagrams, you'll save time and money.

    Multi-testers are readily available online and in stores.

  • Hello! Thank you for your help! New Brake light switch behind brake pedal fixed problem.

  • Awesome!

    We appreciate that you let us know how it turned out :)

     ChiltonDIY subscriptions are great gifts for the right person!