Ok I have a 1991 Mazda929S I drove it up from Dickson Tennesee about a month back and so far I havent really had any issues with it until today I was on my way to the gas station when this guy in a pick up pulls next to me and says your brake lights arent working so sure enough I inspect them and they are out so I go through the bulbs all good check fuses still good even replaced the stoplight switch still nothing. any clues or resources I can use to resolve this ? [:-]

 

check your fuses..

 

See I did that I pulled out my meter and checked them all I am getting continuity on all of them so as far as I can tell they are all good I checked the one under the hood too the stoplight fuse and it was good too any other thoughts or do you by chance have a diagram on the fuse box the one thing it is missing is the cover to the interior fuse box

 

Try jumping across your stoplight switch.

If that brings your lights on then the switch is bad (Yes, I know that you replaced it, but that doesn't mean you weren't unlucky)

If not, then you know the switch might be good (it might still be bad, but it's not your only problem). That leaves three things...

1) Bulbs (sounds unlikely that they would all go, and you've already checked them, so we'll assume that they are good)

2) Fuse (You say you've checked them all but you don't know which is which., hopefully someone here can confirm which fuse it is for you)

3) Wiring. This is the one that you don't want... and I'm guessing it might be what you've got. So, how can you check it? Well, continuity is your best bet. I don't know for sure (I don't have a wiring diagram here) but I'd guess that there are two wires to the stop switch. One is hot (from the fuse) and the other runs to the bulbs. The negative will probably be a connection to the chassis local to the bulbs, it saves on running wires among other things. So, measure the voltage between those wires and the chassis, one of them should have 12 volts-ish on it. The other one should have nothing. Now, check the continuity between the one that runs to the bulbs and the chassis. You should have continuity. If not, you have a wiring problem between the stopswitch and the brake lights. Now you can trace the cable and check continuity at the other end. If you have continuity you now know which wire has the problem and approximately where.

If neither wire has 12v on it then your problem lies towards the fuses, check continuity on both lines and trace the one that doesn't have it.

A good wiring diagram would help, as would a wire routing diagram.

Good luck.

Z.

 

It is a four wire switch there are two wires that go into the plunger that indicates the position of the brake pedal I looked into that and tested it for continuity and it seemed to work as it was supposed to now is there a possibility that there might be a fusible link somewhere prior to the switch ? but ok I will check the switch also I was wondering if perhaps you know if the factory alarm is tied into the brake lights I know it is tied into the hazard lights and horn but the horn didnt seem to work oddly enough[:@] this is getting very frustrating

 

so ok I checked it out and it doesnt seem as if I am getting power to the switch even I checked all the fusible links and they all seemed to be in order but like I said I my horn isnt working now either is there some thing I am over looking ?

 

Well, if you're not getting power to the switch then it's either the wiring or fuses prior to the switch.

I don't have a wiring diagram, (or even a 929) so I can't really help you here.

The only suggestion I have is to trace the wiring and see what you come to. Yes, it is possible that the alarm interferes with this wiring, but I wouldn't think that it should stop the brake lights from working.

Z.

 

Thanks I appreciate the help you have given I still havent gotten it but I think I am getting closer