Hi guys. The car in question is a '98 XK8 with about 37k miles. There have been no mechanical or electrical modifications to the vehicle as long as I've owned it (not quite a year) and none that I am aware of before that.

Roughly 20% of the time, all three brake lights fail to illuminate when the brake pedal is initially depressed. When this does occur, the lights will sometimes, but not always, eventually come on after several seconds of continuous pressure on the pedal. There does not seem to be any pattern as to when this happens, at least none that I've been able to determine. It occurs both with the engine running and with it off, and in all different gears (at least P, R, N, and D).

One item of note that I have discovered is that if the vehicle is in Park, it will not allow me shift out of Park until the brake lights actually illuminate, regardless of when the pedal is depressed. This is evident during those aforementioned times when I push the pedal and nothing happens for a few seconds. All of a sudden, the brake lights will come on and I'll get an audble click in the gear shift area at the same time. Only then can I shift.

All the other lights in or on the vehicle seem to function perfectly, even when the brake lights do not light. I checked the tail lights, fog lights (front and rear), side markers, reverse lights, headlights (low and high), turn signals (front and rear), and interior lights. Nor am I having any problems with the brake lights illuminating when the pedal is not depressed, which appears to be a common problem for this model.

Thanks in advance for your help!

 

The connector at the tail lamp housing has a history of burning up the ground wire. Check that. If that is the problem, it can easily be retrofitted with a better ground wire

 

In addition to a chronic brake light problem with loss of ground connection the brake light switch at the pedal is also a chronic problem with the early cars. The switch problem symptoms usually shows up as something else entirely.

 

The brake switch was my first thought as well, especially since the interlock is not disengaging. So, does the following sound like a reasonable course of action?

Check for voltage at the switch. If voltage is good, remove switch, clean and re-assemble. If that fails, replace the switch.

 

In case anyone else stumbles upon this thread: Replacing the bake switch eliminated all of the symptoms.

 

Ooh rah! Thanks for letting us know. I hate those threads that never get resolved.

By the way, your writeup in the other thread showing how to replace the switch motivated me to replace mine.

So are you at Camp Lejeune or Cherry Point? (and by Lejeune I'm including New River, Camp Geiger, Camp Johnson...)

 

Yeah, me, too. I wanted to wait awhile to confirm that everything was squared away, then I kind of lost track of time.

I saw your response in the Brake Switch How-To. It was indeed a royal PITA getting the studs lined up. I do have to say though, that things seemed to move much more quickly once I realized I had been trying to put it in backwards. I bet I spent over an hour in total contorting myself like some yet-to-be-baked pretzel while trying to figure out what the hell was going on up in there.

Neither - I live in Winston-Salem and work in Greensboro. Check your PMs for a little more info.