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Topic: Brake Light Bulb (Read 491 times) previous topic - next topic

Brake Light Bulb

In the last several years this 270 has gone into what seems to be limp mode four or five times, always after running on the freeway for a few hours and pulling off. It recovers in a minute or two. At first I thought it was fuel filter but no. I have determined that it is in all likelihood related to the King Throttle Control which was rebuilt in 2009. Anyhow, the King diagnostics point to a bad ground associated with the brake lights so I figure I'll replace the bulbs and make sure I have a good ground for the brake lights and for the pressure switches up front.

Two questions:
1. The present bulbs are Sylvania 3457k and are, of course, incandescent (can't use LEDs according to the King documentation). Prices are all over the map at between $5 and $25 each and none of the 3457s are numbered with a "K." So would any 3457 incandescent work?

2. Has anyone added another ground to the brake lights. How did you do so?

Thanks.
jor
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Re: Brake Light Bulb

Reply #1 –
John, We added an inside brake lite on front of bed. This bulb is incandescent. Motorhome rear taillights are LED on our coach.

Found one of the King plugs has green, blue/black, black & red wire colors on the side of the plug wired to King Control. On the other side of this plug, the RED wire is connected to brake-light switch & rear tail-light brake-light bulbs. Tap this red wire to inside brake light. Find any ground for inside brake light bulb.

Inside brake light is an indicator when rear brake lights are on and also a notification of a sticking brake light switch (which would prevent King Throttle & Cruise from activating.

When brake light switches are off King can see the bulb ground on the brake light circuit 12v positive wire.  King Cruise will turn off if it sees 12v positive on this wire and throttle will go into limp mode.

Barry

Re: Brake Light Bulb

Reply #2 –
I wanted to follow up on this post. The King diagnostic tree pointed to a bad brake light ground. I ended up cleaning up the tail light sockets and installing new 3457 incandescent bulbs as well as  cleaning up the tail light grounds and pressure switches up front.

I also unbundled the four King Control plugs to give them a look. I noted that one of those plugs had a wire that had been tapped with the tap wire running to ground. Barry was giving me a hand on this project and advised me that Foretravel had added a ground wire to some units that had problems with the King unit so it's likely this is one of those rigs. On mine they had tapped into the wire very close to the plug and I noted that the wire had frayed so I'm thinkin' my problem could well be this bad ground. Anyhow, I wired around the plug and installed a nice shiny ground. I'm hoping this cures my intermittent limp mode issue. I am also thinking about installing a faux brake light like Barry did.

Anyhow, if anyone has this issue, check to see if you have this added ground.

93 225
95 300
97 270
99 320