Cruse control fault

[Alitis007]

Hi everyone, the other day i reversed the polarity on the eye level stop light socket so i could fit a LED type globe in it but on the weekend while i was driving with the cruse control on i switched the lights on because it became overcast and started raining and the cruse turned off, when i held down the set button the cruse light would flash but not work. When i turned the lights back off it started to work again.

I haven't scanned the ECU yet or rewired the light back to how it originally was but i was wondering if anyone has come across this fault before??

Cheers

[Yendor]

I think you will find it's most likely caused by leakage from the LEDs in the stop/tail lights then by swapping the wires at the high mount stop light and fitting an LED.

When you replaced the high mount incandescent bulb with an LED this changed the resistance in the stop light circuit, this allowed the voltage on the stop light circuit to rise when the headlights were switched on because of the stop/tail light LEDs. Some people have stated this voltage rise can be high enough to cause the dash lights to come on when they put their foot on the brake.

The cruise control see this voltage and thinks the brakes are being applied so it doesn't allow the cruise control to set.

You can either refit the incandescent bulb back in the high mount (there's no need to swap the wires back) or fit blocking diodes to the tail lights.

[Alitis007]

I have had LED stop/tail light globes in the bumper bar for about 6 months and didn't have a drama.

I'll switch the globe later and see how i go...

Thanks again Yendor your a champ!!

[Alitis007]

Actually i do have resistors that are supposed to be wired in to the indicators to bump the resistance up so the flasher can doesn't flash fast, i could use that to increase the resistance.

First i'll try the globe then try the resistor!!

[threedogs]

Seems a very common thing with the LEDs not providing enough resistance.
Alitis I have Flasher relay and 50 ohm resistors here.

[Alitis007]

All good TD i have about 6 resistors if not more lol you can buy CANBUS LED's that have it inbuilt for Mercs and BMW's that have a globe warning system but i'll get it sorted when i knock off from work tonight!!

[Alitis007]

Got it sorted with the resistor, heres some pics
28479
28480
28481
28482

[Yendor]

It's good when it's an easy fix.

[Alitis007]

Even easier if you leave the normal globe in lol

[Yendor]

Even easier if you leave the normal globe in lol

But where's the fun in that :D

[Alitis007]

Mate the fun is when all the older mechanics i know tell me to leave it the way it is and don't play around too much and you know your in too deep to back out so you gota finnish what you started and turn a couple of mods to totally modding everything lol

[Yendor]

The funny thing is I bet when those mechanics were young they were into modding.

It seems it only becomes a bad idea once you get older.....apparently.

[Alitis007]

The funny thing is I bet when those mechanics were young they were into modding.

It seems it only becomes a bad idea once you get older.....apparently.

Your 100% right mate, and when you tell them that they say one day you'll see that theres nothing like hopping into your car turning the key and going without having to worry about anything, or you get the, theres a reason why it left the factory like that , so it lasts !! Lol