Hi, I have a 94 Mazda mx-3 gs K engine ATX.

Was driving and the radio dies, look at gauges and rpm and speedometer go dead. Car runs till I drive a little ways and put on brakes and then it dies. I was going out to eat so went in and then came to check on car. EVERYTHING works and car starts.

Time to go, same thing again, radio, gauges, put on brakes, car dies. I get a jump. This time it idles for a while but when I step on the brake pedal the rpm gauge goes dead!

What is going on here. I have replace the alternator and battery about 7 months ago. Why does it idle fine until I press on the brake pedal?

Please help.

Thanks

 

There is obviously a short somewhere. Pinpointing the location of it is difficult. I would look at wiring and connections where a lot of circuits come close together. Fuse blocks and harnesses that go through the firewall for example.
One way is to run the engine and tug on harnesses. If the engine stalls you know which harness to check further. Look for obvious signs. Things like chafed insulation, frayed wires , corroded connections etc.

It will take some persistence. I know you are not the type to give up!

 

Yep, you more than anyone else knows I'm not the type to give up. I shall do as you advised!

Thanks

 

Some more thoughts:
1. Check the relays in the power distribution box. Sometimes you find 2 or 3 of the same kind of relay for different circuits. If you switch them around and the problem moves to a different circuit you know which relay is bad. If the problem persists without changes you can assume the relays are fine.
2. The switch that gets used the most is the ignition switch. I would have a closer look.
3. The electrical circuits all need proper ground. Make sure all ground connections to the body and the engine are good.
4. Even though they are fairly knew, consider having the alternator and battery tested. Parts stores do it for free.

 

Well, it may be a short or relay but this is a symptom of a disty that isgoing bad… extremely common in the v6 MX-3s.