1949 98 4-door. Brake lights work intermittently. Drove the car 70 miles, no brake lights. Sat in the garage for a week. Took off the connectors to the brake switch, tried to take the brake switch off, no go, could not get the torque on it without a lift. Put the connectors back on, no brake lights. Brake lights would come on when I jumpered around the switch. Next week, without doing anything to the car, the brake lights worked. 3 days later drove it to a shop to have fluids drained and filled, etc. brake lights worked the whole way there. Picked it up, Wheel cylinders and rubber brake lines had been redone, I'm assuming brakes were bled. Brake lights did not work the whole way home. 4 days later, without doing anything to the car, brake lights work again. It is a very simple system, shouldn't be a grounded wire as the lights will work or not work without the car moving so no way for the wire to become grounded/ungrounded. I'm at this point assuming it is the switch. Sound like a good diagnosis? I really don't want to try to replace the switch unless absolutely necessary as I am afraid with the lack of being able to get at it from a good angle, I might break it off in the master cylinder, then I'd have gotten myself into a fine mess. Any help here is appreciated.

Thanks,

 

I assume this is a brake fluid pressure switch.

It's probably bad. You should replace it.

Sorry.

- Eric

 

Yes, it is. That's what I figured, just thought I'd see if anyone could think of something else it might be that I hadn't thought to try. I wasn't sure, but I suspected, if a switch like that would go intermittently bad.

Thanks,

 

If you don't have the tools or skills, just have someone else do it.

 

Yeah, I might have to. Even on jack stands there's not enough room to get leverage on the damn switch to turn it. My arms are too long from elbow to wrist . If I had a lift, or if I wasn't hesitant to move my jack stands taller (call me a sissy, but taller jack stands with 4000 lbs of car above me makes me nervous) it would be a lot easier.

BTW, I've got mad righty-tighty, lefty loosey skills. Almost caused a problem when I went to take the drivers side wheels off the car though. Damn things are left hand threads . Luckily I wondered why the lugnuts had an "L" on them.

 

Oh, forgot to mention, taillights and turn signals work properly.

 

Probably a bad switch as mentioned above but it also could also be a broken wire that will make contact indeterminately.You might check the contacts at the switch before you pull it.....Tedd

 

If I jumper at the switch, the brake lights light (even when they don't light when you push the pedal). I guess that should have been enough evidence for me that the switch was bad, but sometimes I over think these things.

 

Can't fault you for making sure you've run through all the variables. Hopefully when you change the switch all is good.