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Randomly the car shuts off while driving. Turns out the main relay under the dash failed. Replaced it and now as soon as the key goes to 2 the 15a engine fuse on the kick panel fuse box blows. It's instant. I'm at the point now after troubleshooting for a few really long days where EVERYTHING is disconnected or unplugged.
The only real progress made is that the fuse will only blow if I plug in the main relay. Looking at the wiring diagrams I can't really tell where the wires go after they leave the fuse box. It's 2 black with white stripe wires. One large gauge and one smaller gauge.
I'm having a hard time figuring out where to go from here. Every plug is disconnected so if there is a short, i dont know where it could be shorting out. I also removed every fuse from both fuse boxes except the 80a main. The power wire and the 2 prong plug on the alternator are removed as well.
Any insight on what I should be looking for or what tests I can do would be much appreciated. If it helps any, I did a continuity test from the fuse box to the pins at the ecu. Pin 3i is a ground for me. According to the pin out it's supposed to be 12v if I'm reading that right...
yes, definitely a short. with the harness as pulled apart as it is and the car only having 22k miles and being SUPER stock, im convinced the short is internal to a component and not actually a wire touching something. im keeping an open mind though.
i may be talking about the wrong relay since the one im talking about is a 6 pin plug with only 5 pins in it. right next to it is a 4 pin plug. there wasnt anything in there to begin with.
I read again and seen you said under dash so you unplugged the circuit opening relay and the fuse didn't blow?
Ok, do this:
Disconnect Circuit opening relay.
In that connector you will find a L/R coloured wire.
Take your multimeter set to lowest ohm setting.
Test that wire in relation to the black wire on the same plug(maybe you could verify that this wire is definitely grounded first).
You should have no continuity.
Edit: Actually you would also have to disconnect the fuel pump relay in the front bumper for the test to be worth anything. If this is left connected you might read resistance(not sure).
Last edited by Rotary Alkymist; 09-02-19 at 01:22 PM.
correct, the fuse does not pop with the circuit opening relay unplugged and the key on 2. as soon as i plug it in, it pops.
so i have been making a mistake this whole time. the main relay next to the coil has been plugged in this whole time and i have a pretty high resistance reading between the 2 wires you said to probe. please watch the video. thank you very much for your help. im all out of ideas on this one.
It seems that your wires don't match the FSM. This can be an issue with the 2nd gen.
Forget everything I posted.
Try this,
there is a relay that looks like a heat sink close to the passenger headlight. It has fins on it like a motorcycle head and is made of aluminum. That's the fuel pump resistor relay. Unplug it and turn your key ON. Hopefully it doesn't blow your last 15A lol(man I'm dying over here).
About your lacks of fuses: for testing purposes a 10A or even less would work... the circuit when running properly would never see 10A. If it blows a 5A something is wrong. What I'm saying is if you run out of 15A use 10A or whatever you have until you figure out the issue and then throw a 15A when you can.
Last edited by Rotary Alkymist; 09-02-19 at 10:28 PM.
looking under the airbox for the resistor and it does not exist. the only thing under there besides some relays is the object on the left
everything under there and in that little area in front of the radiator is unplugged. i unplugged the single black connector near the fuse box that loops into the charge harness. with it unplugged the fuse does not pop. i unbolted the charge harness from the starter as well just to rule it out. so as of now, the only thing plugged in at the charge harness is that single black connector. and i was mistaken about the year of the car. its an 86 if that matters. also the MAF is unplugged
i also tried that with the battery completely unplugged, both terminals removed and there is still 0.04v on that pin. I. DO. NOT. UNDERSTAND
another note, when i probe the pins on the fuse box for the 15a, the lower pin is battery voltage and the upper pin is ground. im pretty confident this is wrong. the 7.5 meter fuse next to it shows this same result except instead of showing 000 on the multimeter, it shows 045. im having a hard time finding the wiring diagram for these wires. im looking at page 50-12 but it only shows it running to the ignition switch.
I'm a bit confused. You say you're using a circuit opening relay from an FD? An FD circuit opening relay only has four pins. Where did you get that relay?
How did you test yours?
Last edited by Rotary Alkymist; 09-05-19 at 08:27 PM.
not the circuit opening relay... just A relay. i tested it using the multimeter set to continuity. there is no continuity on any of the pins to any of the other pins. thats why im not using it. testing other 5 pin relays that are known good, there is supposed to be continuity between 2 of the pins. i forget which 2 but they all tested the same. the one in the car has no continuity at all.
You're gonna need some wire and alligator clips to do this properly.
Take the original circuit opening relay, draw out a pin diagram and label the pins with their wire colour.
Now that you know which pin goes where do this:
Cut a generous length of wire and connect alligator clips to both sides of the wire.
Take your test wire and connect it to the B pin and take the other side and connect to ground.
Now make a Y shaped wire but conecting to short wires to one and connect alligator clips to all sides. You should have a wire that is Y shaped with three alligator clips on it.
Take that wire and connect the two short wires to B/W and B/R.
Finally touch the other end to the positive battery terminal.
i will do this test. im more of a visual learner lol so its a little difficult for me to translate your directions to the real world. if the relay does click, where do we go from there? also, if it does, what would be the explanation as to why the fuse blows with the current one plugged in?
i tried to follow your instructions and could not translate it to the real world. im sure its written plainly but i could not understand. i instead performed these 2 tests and the relay passed both tests.
i have to say though, when i started this process there was no continuity from any pin to any other pin on this thing but now there is. if the problem this whole time is an intermittent relay i think i will finish a bottle of something tonight lol
i am going to reassemble everything and see what happens. dont want to speak too soon but i will go ahead and THANK YOU for your help tremendously.
alright, i have to say i get to finish a bottle lol. its an intermittent circuit opening relay. you were 100% right about the pin out of the FD relay being different. im not going to plug it back in to verify that it will blow the fuse to double verify the pin out of the relay is different.
i put the car back together and everything works as it should...........mostly.
the new problems:
key chime turns on with the lights and stays on
tach works during cranking and for ~3 seconds once it starts and then it stops reading
the key chime issue isnt really that big of a deal except it tells me that something is backwards i would think. it doesnt come on with the key in the ignition like normal, it only comes on when the lights are on any position, key or no key, running or not running. the tach is really what i care about. it will consistently work when cranking and for those first few seconds when running and then stop reading.
again, thank you very much for the help. once i tested that relay and it showed no continuity in any configuration, i wrote it off. i didnt even consider the possibility that the relay i replaced it with was pinned differently. thats really a way to think outside the box imo.
would you be able to identify these plugs? the one with the circle is near the main relay
Don't worry about the chime for now. It is supposed to chime when you leave your lights on.
EDIT: As for the tach, clean the connectors at the trailing coil. Make sure all the pins are clean and no signs of corrosion. In particular the Y/L wire.
Last edited by Rotary Alkymist; 09-09-19 at 04:05 PM.
i put the car all back together and it just started. i dont recall what was different if anything at all. some time later, it started doing it again and the battery terminals were changed and that fixed it. it may or may not has happened since. the person who owned the car, sold it shortly after it happened the second time.
09-01-19, 03:37 AM
