RotorMotorDriver

iTrader: (1)

Ok, guys, this is bugging the hell outta me. I keep "blowing" my main fusable link. Ill be driving down the road, everythings fine, then all of a sudden, my volt gauge starts reading 15-16 volts, my tach starts jumping EVERYWHERE, the radio looses power for a split second evertime I hit the brakes, the stop lamp light comes on as long as the brakes are on, the car just fuckes up in general, but runs fine. Anyway, I hop out and check the main fuseable link (first time it happened I thought it was a bad ground or something), and my voltmeter says its not conducting, even though its conducting just enough current for the stuff inside to **** up. So I have some spares from a junk yard, I pop a "new" one in and everything is normal. About 3 weeks later, it all happens again. Its getting annoying as its happened 4 times, and Im outta new links . Is there a way to upgrade the box to something like an inline bus fuse holder? Like a fused distribution block for car audio? I know they make them, but how many amps does it take to fry each link? I need to find out why it keeps doing it, but I dont know where to start. Theres no pattern, like if I use something that I normally dont or anything, it just kinda happens. I was thinking its just something just BARELY over drawing the circuit and causing it to SLOWLY deteriorate the link, then one day, the link is just too worn out. I dont know what would cause that though...A small light bulb thats the wrong one and too bright or something?

~T.J.

RotorMotorDriver

iTrader: (1)

Ok, this is what Im thinking...One input, three fused outputs, and uses "standard" AGU fuses from 10-60 amps...More than enough unless they are under 10 amp links. Would this work as long as I get fuses in the right amperage ratings? I dont see why it wouldnt...

~T.J.

MarkPerez

What was the last thing you did electrical, before you started having problems ? trace your steps backwards.
were you fooling around with the guages ? under the dash ? under the hood (dumb question) i've read that when the tach goes screwey,, it's a coil.. what do your fuses look like under the dash, any blown ?when the car is running good are any wires warm or hot ?

rotor vs. piston

I've seen the "how to's" on converting to blade type fuses. But no one seems to know for sure what amp fuse to use for the main and the light motor. I think they used 80amp for the main and 40 or 60 for the lights. Also I remember someone using a Second Gen box.

Anyway my car did the same thing and it was just bad fusable links (I too use old link off other cars). Carosion (sp) also helps to agervait the problem, so take some time and clean the contacts.

RotorMotorDriver

iTrader: (1)

The only thing I suspect is, odly enough, a damn light bulb. I had one burn out on me in the center console and I replaced it with one that "looked the same". Other than that, nothing has changed, it just started doing it a while ago.

~T.J.

rotor vs. piston

Ya, that block will work. Just make sure when you do this to keep an eye on everything for a little while. You could also just put in low amp fuses and work your way up until they don't blow, just make sure the other links and fuses are not blow out while your doing this.

RotorMotorDriver

iTrader: (1)

I myself also thought that the fact that they had been used would affect it too. I just cant find new ones in stores, and Im scared that Mazda wants an arm and a leg for them, which is why I want to convert to something more "readily available". The fuse box I showed above uses standard AGU fuses, you can get them in 5 packs for like $5. Theres an auto shop that sells fusable link wire in spools so you can drimp your own ends on (closest Ive found to being helpful) but once again, I dont know what rating wire to buy...Plus I have to buy the wire and the ends everytime I run out, which would cost more in the long run than the AGU fuses Im sure...

~T.J.

RotorMotorDriver

iTrader: (1)

That was my though, but I dont wanna jump from say 15 to 20 amps if they are suppsed to blow at 16...I want to know a "real" number. I wish I had a brand new fusable link I could sacrofice in the name of science. Id hook it up to my uncles regulated power supply and slowly increase amperage until it blew lol.

Also, I thought they were all the same rating? If they arent, maybe I have the wrong size link in mine each time? Ive seen a few junk yard cars with paperclips and wires and hair things and everything else in place of a main link, so I think this may not be too un-common. I bet Mazda might know...Ill try and call them tomorrow or something.

~T.J.

rotor vs. piston

Mazda Trix still sells them, the only place i've found, but I think I remember seeing ~$5.00 for the main and just a little cheaper for the other two. Converting to a newer style fuse block is on my "to do" list as well. I, at one point, had to drive my car with the two ends of the fusable link twisted back to gether. It still does the same job.

rotor vs. piston

Ya bro, the one in the middle is the main link, I can't remeber off hand but I think it's black and the two outer one's are brown.

RotorMotorDriver

iTrader: (1)

Ok, at least now I know they are different. I just went to MazdaTrix's website, and they sell either black or brown "fusable links" for 79-85. They dont say what the ratings are though...But I know there is one black, and two browns. I just need to know what their rating is. They have the "all-78" category, and it says theirs either a 50A or a 70A "main lead fuse", but Im guessing thats different than the 79-85's "fusable link"?? Hmmm...

~T.J.

rotor vs. piston

No one knows what the amps really are for those damn things. The point of that type fuse is to allow high amps for a period of time, so there is really no said rating.

RotorMotorDriver

iTrader: (1)

There has to be though...Damn it. This pisses me off sooooo much. At $5 a pop, those fusable links are EXPENSIVE! As I said earlier, I can get a 5 pack of the AGUs for like $5...

~T.J.

EDIT: I just emailed MazdaTrix and asked them. Lets see if they can tell me...Will post and let you know, unless anyone else out there seems to know.

Spieder

Hmm, the only time I had that happen was when my battery terminal was loose. You have something shorting out in your electrical.

Do your links blow at night or in the day?

Do you have an amp for your radio? Any loose radio wires?

Check your wiring aroudn the alt. Those vacuum tubes will conduct electricity. Just like tires, because they have silicon in them. I had some problems with my alt flickering in my dash, I happened to pop the hood one night and saw arcing. The wire that goes to the solenoid on the carb was bare and sparking against a stupid vacuum line. Wrapped it with e-tape, no problem.

You also might try hooking a multimeter to a 12volt lead in the car and watching it while you drive the next few weeks. I did that once out of curiousity and mine stays at about 14.4 volts.

RotorMotorDriver

iTrader: (1)

Well, I dont see how it can be a short because a short should pop it "right away" right? The terminals are tight, and there are no loose wires behind the dash around the radio. I installed it myself, and taped over anything not used. The link (only the main one blows) has blown both night and day. Like I said, no pattern to it. Its just like the link fatigues and blows because something is BARELY overdrawing it.

~T.J.

Rx7carl

Your stop lamp light means you have a brake light bulb out. Theres a circut called a brake checker that does this function. A 2nd gen block is a common upgrade and you end up with one extra output, and it uses big fuses, not links. When you notice the problem again try this. Pull over, leave the car running. Then pull one fuse at a time (except for the engine one so it keeps running) and see which circut your problem is in.

85RX7GS

iTrader: (1)

I've seen a procedure on here for installing an FC fuseblock in place of the fusible links. This way, it'll look like a factory-Mazda part. I'll try to find the procedure.

85RX7GS

iTrader: (1)

Here it is, the Fuse Block Conversion Procedure:

Converting from Fusible Links to a Fuse Block

rotor vs. piston

If the fusiable link gets to many amps it wont just pop. It will take about 5 to 10 seconds to burn into two pieces, I've watched it happen. Let us know how easy the conversion is though, good luck with your ride. Don't let it get the best of you.

inittab

First off, if you're blowing fusible links, then you have a major electrical problem!

The Haynes Manual **buy one they're cheap** says that there are three fusible links. The main one is 1.25sq (square per millimeter). I have some conflicting info about the two others. The Haynes says they're 0.35sq but the factory manual says they are 0.3sq. I have no clue what "square per millimeter" means in reference to fusible links so I can't help ya there. Anyone else know? But, looking at the wiring diagram I can tell ya this. Everything off of the main fusible link is fused EXCEPT the alternator and starter motor off the start position. So by that logic, I'd start by checking or replacing the alternator. Good luck!

Spieder

You don't want to upgrade that fuseable link trust me. Don't do it.

The reason it is blowing is that you have a problem that needs to be fixed. If you change the link, that means instead of your link blowing, you're going to pop somewhere else.

And fusable links don't wear out. They are designed for a power rating. I believe power is I^2*R. Once the power reaches a point, the link will blow. Below that it won't. There is no wearing out, you need to understand that. Just like the fuses under your dash, once amp's (I) go over the rating they are toast.

Have you checked the voltage and amperage at the fusable link? Do this before anything. To check the amperage, disconnect the line leading to the link, then connect the multimeter between it. Never measure current across anything (you'll blow your multimeter at miniumum) always in series. To check voltage, just attach the + multimeter cable to the link and ground the negative. Then you'll be using the equivilant resistance of the car which is what that link is seeing (R).

I can't stress though, changing the rating of your fuses will only cause another component to fail. No one else is blowing links with stock gear so it's not a design flaw.

You can also have an intermittant short somewhere. I woudl start by removign and cleaning all the starter wiring down there since it's subjected to most environmental hazards. Then start lookin around.

I used to blow the fuse that ran my window every month. If the lights were on and I rolled up the window then pop. I took out the carpet and seats and checked. Turns out, the previous owner wired a CB and just plugged the lead into the front of the 15 amp fuse with a 14 guage wire. Somehow, he was pulling too much power. I removed all that stuff and now I haven't blown a fuse in 2 years. I can't tell you why it made a difference since the CB was no longer there. But just taking out those wires and tossing them solved the problem.

RotorMotorDriver

iTrader: (1)

How can it be major if nothing is wrong for 3-4 weeks and everything works fine?

I have a Haynes manual, but its at my other house.

The alternator has been iffy since the day I got it. I got it to replace a messed up one, dropped it in, and the stupid this went wacko on me (like a burned out voltage regulator) then I took it back out, had it tested at two different places and they both said its fine, so I put it in with a new battery and no more problems AT ALL. Voltage is dead on at 13.5 all the time.
Which is why I want to find out what size the links are. That way I can get the right size fuses while I diagnose the problem. I cant afford to keep blowing and replacing links at $5 EACH while I hunt this damn problem down...

RotorMotorDriver

iTrader: (1)

Ok, well tonight my battery went dead, so I think that my alternator is giving me problems again, even though its brand new. Anyway, I started another thread about it. I think the alt has something to do with the links frying because as innitab says, its the only part of the circuit not fused or whatever.

~T.J.

RotorMotorDriver

iTrader: (1)

Well, I dont really mean to bump this all the way to the top, but I just saw it when I was searching for another post, and thought Id leave an update for anyone who searches and finds it.

I replaced my alternator (again!!), and its been over a month now, and no more links frying. Everything seems fine. Guess the alternator was it . Just to re-cap for those at home, my origninal alternator went out. I bought a replacement, it was the one with all the problems, but it turned out to be bad as well. Now I have another alternator, and no problems . I have rock solid voltage at an idle, and everything is great .

~T.J.

85RX7GS

iTrader: (1)

Glad to hear it!