Ive replaced the stoplight switch, checked all the bulbs and wires, checked the interior fusebox for blown fuses. it keeps blowing the btn fuse under the hood. i put one in and reconnect the battery and the hazard lights go on for a minute then the fuse blows. i have the dash apart and checked for shorts going to the stereo because thats not working either. my brother my or may not have reversed the polarity when trying to jump start the car but he's a ******* and does'nt remember...im wondering if the diodes are bad in the alternator. if you try to put a fuse in without the battery disconnected it blows that btn immeadately. but like i said if you disconnect it the lights go on for a minute then it blows. but just the hazard lights, no other lights will work. running,brake,interior,radio,horn,etc.. i am stumped. he said the battery goes down after it sits and he has to jump it. the car seems to run fine otherwise tho.
If you do not want to bench check the alternator you can check the diodes while the engine runs with a tester having a diode function. Or disconnect the power cable and check the small wires against the case which should be grounded with an Ohmmeter. The purpose of the diode is to be a one-way gate for powerflow. Even momentarily reversing polarity could have smoked the diodes. If the diodes are bad, they will ground the power into the alternator case. If regulator is external have that checked too.
Also you can get a wiring diagram free at Autozone.com by registering your vehicle. You could have smoked a relay and it is fried and failing to disconnect its contact points.
Hi Lee and Chuck, Seems you have a serious short circuit in your vehicle. The fact that when the vehicle stands it will need to be jump started would seem to confirm the same. The power seems to be draining somewhere! The fuses which blow will give an indication of which circuit is shorting. If your brother wired in a music system or radio, disconnect it and then see if the fuses still blow? If they stay fine you know where to start. The music system is connected to the lights for night illumination of the controls. It may be that the earth connection has been mixed up with a power cable? If the vehicle runs fine during the day and does not give problems when restarting, it would be doubtful that there is damage to the alternator. You can check it fairly easily by connecting a test meter to each of the terminals. Start the vehicle and if while cranking the voltage drops below 8 volts, get the battery replaced. If it remains at about ten during starting that's fine. Measure the battery voltage before starting and confirm 12 volts. Once started the voltage should be at about 13 volts if the alternator is charging and when the horn is pressed and the wipers turned on together with the heated window, the voltage should climb to about 13 and a half volts. If the voltage remains unchanged or drops the alternator is damaged. Usually the head lights would be turned on to carry out this simple test but as the fuses blow you can do that when you've found the short circuit. Good luck and best regards John
SOURCE: 90 miata lights
> Any suggestions or reference to free wiring diagram downloads??
It doesn't seem likely since most of that kind of material is copyrighted works. I think they would take offense to putting it on the web.
You might get some help (or even emailed diagrams) from a fellow owner.
Check here:
http://forum.miata.net/
Good luck-
SOURCE: No power at all. Only head lights work
Ypou have blown the main fuse is held in with two bolt left side of engine compart mentunder a black cover i think is a 60 or 90 amp fuse. hope this helps.
wayne
SOURCE: brake light fuse
Take a look at the wiring to the brake lights. It is quite possible that over the years one of the wires has rubbed against another enough to short out, causing the blown fuses.
SOURCE: My battery dies after 3 days of sitting - I pulled
short circuit drains the battery. check connections.
SOURCE: Why rear brake lights not working on 1990 Mazda
You'll have to inspect the brake light switch at the pedal box assy. Damaged switch or wiring could give the previous symptoms you describe.! Good luck
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thankyou for all your feedback...after i get in there today i will let you know if that was the problem or not.
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