Brake Lights not working - 2003 Alpine 36MDDS

[Astasoftride]

Today we found the brake lights not working. Here is what I have found so far

None of the three brake lights function (left/right/third)

The trailer plug DOES show power when brake pedal pressed / no power when pedal released.

Brake light bulbs visually look good

15 amp fuse up front replaced (the old one tested good)

Booster pump does come on when the brake pedal is pressed (Cummins off).

There is a converter for the trailer plug. The converter for going from the three light system (Alpine tail lights) to the two light system (four prong trailer plug).

I tried to test the left tail light connector - It tested good on power for the tail light - No power for the brake light.

I did not have any strange behavior this past weekend from the cruise control. (Failure to engage or disengage).


What confuses me is that the converter is getting a brake light signal - but it is not getting to the actual brake lights?

Any suggestions on how to trouble shoot further would be helpful.

thanks

Mike

[Funbus2000]

I recently had similar issues , except I lost all lights eventually. It was a failed conversion box that caused all the problems. When I described the issues to the auto electrician , he knew right away what the problem was. I lost all lights except the left turn signal bulb on the left mirror. Good luck.

[Funbus2000]

Also check your fuses. Mine all eventually blew.

[Busskipper]

Originally Posted by Astasoftride

Today we found the brake lights not working. Here is what I have found so far

None of the three brake lights function (left/right/third)

The trailer plug DOES show power when brake pedal pressed / no power when pedal released.

Brake light bulbs visually look good

15 amp fuse up front replaced (the old one tested good)

Booster pump does come on when the brake pedal is pressed (Cummins off).

There is a converter for the trailer plug. The converter for going from the three light system (Alpine tail lights) to the two light system (four prong trailer plug).

I tried to test the left tail light connector - It tested good on power for the tail light - No power for the brake light.

I did not have any strange behavior this past weekend from the cruise control. (Failure to engage or disengage).


What confuses me is that the converter is getting a brake light signal - but it is not getting to the actual brake lights?

Any suggestions on how to trouble shoot further would be helpful.

thanks

Mike

Need

Hot and Ground

Then Good Bulb that can connect

I've had all be bad so .....

Most likely the ground from your discription

Best of Luck,

[Jeep401]

I've also had the converter box go bad.
In my case though it only effected the trailer plug. I would suggest testing with a non LED test light instead of a volt meter.
I wasted hours troubleshooting mine. It showed voltage but wouldn't light a test light.

[Astasoftride]

Thanks for the suggestions. It turned out to be the converter box. Everything works again.

[Jeep401]

Originally Posted by Astasoftride

Thanks for the suggestions. It turned out to be the converter box. Everything works again.

Glad you got it figured out.

[arcaguy]

Originally Posted by Busskipper

Most likely the ground from your discription

Best of Luck,

THIS^^^^^^

[tonka96]

Their is a brake light switch I believe it's mounted below the floor on the brake linkage.