After putting in a new battery and starter on my 84 fb i get no power to anything but the headlight switch.. no interior lights, no horn and worst of all no turning over..I bought this car from a younger kid who seemed to know very little about the car and now i am scared there is more wrong than what he led me to believe.


troubleshoting an electrical system is pretty far past my knowledge of cars but i am going to see what i can find out..

I did hook the battery up backwards the first time I hope Mazda was smart enough to put a protect on the electrical system against cross wiring. DOH!


time to check out the diagrams

 

Check all of the fuseable links in the engine bay near the driverside shock tower.

 

I found 3 on the shock tower and all 3 are good.. are there an other fuses besides the 3 links and the panel under the dash?

after looking at the wiring diagram.. it's for an 85 hope it's the same, seems to be a fusible connected to the hot start relay circuit. where would this be?

 

Sometimes a fusible link will look alright, even though it is burnt. Take another hard look at the center fusible link.

 

I actually tested them with a tester and all 3 have continuity.. I have the wiring diagram for an 85 but can't find the 84 manual anywhere.. I did order one from mazdatrix along with the FSM but that won't be here for awhile.. anyone have a link for an online wiring schematic for the 84 12a cars? My 83 is a bit different than the 84 if i look at the connectors by the brake master and I do have the manual online for the 83 but it does seem a bit different.

 

Found the 84 wiring diagram at http://www.wankel.net/~krwright/file...ingDiagram.pdf

first trying to get it to turn over.. it looks as if i need to start at the ignition switch and work my way out from there.. If it is as simple as the switch not getting current should be an easy fix

 

ok after a bit of looking seems as if Ken was correct again although the fusible link tested ok with a 12v tester it seems as if the link or the block has an intermittent break.. dunno if it's the link or the block itself but some cleaning of the terminals and replacement of the link should fix the issue..
thanks ken for the quick response and we will see if this is the only problem

 

a good choice to upgrade those too is getting these: If you get the long leged ones they're a bit better, you will have to cut off just a little bit for them to fit in but they work just fine. The order that i have them in is 40/60/45AMP from top to bottom. No one is quite sure what the stock ones are but this is around there ... i think alot of people actually do 40/60/40 or 30/60/30

 

it took me a while to search the forum and find those but that is what i picked up from the parts store.. I am going the 30-60-30 route or even 30-30-30 until it blows.. I also picked up a multimeter to try and test the amperage draw through the fusible links, so if i can figure out the max amperage with the systems at full load should give us a pretty good idea of what rating link to use..


so according to this chart i found here http://www.rowand.net/Shop/Tech/WireCapacityChart.htm

the 30-60-30 seems to be correct measure your wire in mm and check the chart for max amps