Brake Lights On When I Turn On Headlight Switch

[mikecollie]

I have a 2000 Monaco Diplomat with a brake light problem.

Every thing works fine until i turn on the headlight switch and then the brake lights come on  bright and do not work or get brighter when i press the brake petal.

Turn off lights and every thing works fine again.

Called Monaco and they said bad headlight switch so replaced with new one .

Now my dash lights work better but still same problem  with brake lights.

Anyone had this problem or have any ideas?

[OLDMARINE]

by chance , have you replaced a light bulb in your tail lights recently and used the wrong light bulb . like putting a single contact 1156 bulb into a socket that suppose

to have a 1157 bulb (2 contacts) . this could cause this problem . I  cant see how the headlight switch could cause this . hope this helps

Old Marine

[mikecollie]

I have replaced the bulbs and they are 1157

[abyrd]

I would check the ground connections on the stop light bulb sockets.  A poor ground wire can cause so strange thinks to happen.

Jim

[dickandlois]

Mike, Do you have the owners manual for the coach? Monaco is fairly good about placing information on circuits, fuse and relay location. 

My first thought is a bad ground on the headlight circuit and the brake light circuit is the closest point for the head lights. 

Rich.

[mikecollie]

I will check the ground on the stop light socket next and yes i do have a owners manual that i will try to research if i can fiqure it out. Thanks for your input and i will post what i find out.

[hermanmullins]

If you have a true 1157 twin element bulb it is next to impossible to put in the socket incorrectly. It can only go in one way due the placement of the pins on the sides. One pin is lower then the other on the side of the bulbs brass case.

Please check for a double element, double contact bulb with off set pins. If all three are correct then your problem may just be a bad new bulb. 

Herman

[mikecollie]

Thanks Herman,

I wondered if it could be a bad new bulb. I will recheck it . I thought I might put in a new 1157LL bulb, long life, thought it might be heavier duty, any thoughts?

[wildebill308]

Can't hurt and will remove one more variable.

Bill

[mikecollie]

Up date on brake lights.After replacing both taillight sockets we found a wire hooked up wrong on 7 pin connector that was used for tow dolly brakes.after disconnecting that wire every thing worked fine . the sockets needed to be replaced anyway.Thank for all your input.

[tbutler]

Thank you for posting your solution.  That makes the discussion so much more relevant to others searching for a solution and a bunch of us who now have filed away another cure for a problem.