Fusible link help

[NorWest]

Anyone have any problems with their fusible link located in the smaller wire leading from the positive battery terminal in your trunk? I suspect I fried my fuse in there but I'm not sure how or where to test the fuse to see if I blew it.. I would have to cut through the wire to get a look at the fuse itself and I'd like to avoid doing that if possible.

If anyone has had to replace this fuse what did you replace it with? I believe from what I read that it's a solid piece of metal connected to the wire? Did you replace it with a new fuse or just wire in the same gauge wore to reconnect the circuit?

Some background info on my problem is a no start issue after attempting to jump start someones car. I have 12v at the power point under the hood which I believe to be the larger gauge cable's power supply from the trunk. My main relay seems to be fine and I tested my coil an I have 12v there as well.. I'm stumped.. I'm getting no spark to my spark plugs or my distributor

[oliver.r]

cut it open and check it out, order a fusable link from bmw just in case, its easy to replace

[Quadrajet]

If you had enough test lead extensions, you could use a continuity tester to see if the wire is an "open circuit".

Or take a test light at the terminal under the hood to see if there is power there.

[NorWest]

Alright thank I was able to order a new fusible link so I'll cu it open and check it once it gets here. Hopefully this is the problem cause I'm done with diagnostic crap with the ignition system. I'm just going to throw all new parts at it. Everywhere.

[dontrusthise30]

Just be prepared- often times, the fusible link pops when there is a short in the harness. Something caused it to break. I replaced mine with a high end stereo 50amp fuse, but ended up popping that right away as well. Went through the entire engine harness and found two melted wires. Replaced the engine harness, put in a new 50amp fuse, and been running great ever since.

[NorWest]

Ya that's something I'll have to check for sure.. I was kind of thinking I might've fried a wire or two but I really hope not.

I have a question about the fusible link though.. Where in the heck does the small wire that houses the link run to? And what does it power? I have power to literally everything in my engine bay and my starter works, got power through the coil, my headlights and radio work.. I have no idea what this wire sends power to

[StereoInstaller1]

Here is an easy test for the fusible link: does anything work in your car aside from your starter?

If yes, its good.

If you car will only run the starter and NOTHING else works, its the fusible link.

Seriously, if your headlights, dashlights, radio, HVAC, domelights...if anything works at all, the fusible link is good, end of diagnostics.

Now, what to do if it is bad...personally, I replace them with "Mini-ANL" fuses. I like to use small fuseholders like this: http://www.ebay.com/itm/4-6-8-10-Gau...-/111009587537

Best of luck.

Luke

[StereoInstaller1]

Ya that's something I'll have to check for sure.. I was kind of thinking I might've fried a wire or two but I really hope not.

I have a question about the fusible link though.. Where in the heck does the small wire that houses the link run to? And what does it power? I have power to literally everything in my engine bay and my starter works, got power through the coil, my headlights and radio work.. I have no idea what this wire sends power to

Pop your hood and look in the right rear corner of the bay, on the firewall. You will see the big 0 ga cable for the battery and a small terminal near it with the 8ga "fused" run. That one small wire runs every single circuit in your car except main starter current.

BTW, if you are new to BMW electricals, remember this phrase: Brown is ground the world around, except in America.

In Euro cars in general, black is positive. BMW in specific, brown is ALWAYS a ground, but if it has a stripe, it is a "switched" ground, or in some way used as a return for some other function...just remember brown is ground.

Luke

[ForcedFirebird]

Hey Luke, isn't the fuse box run on the double wire that is attached to the battery clamp 10mm bolt, not the fusible link terminal? Thought the fusible link only ran the DME?

Anyways, don't cut anything, just see if you have 12+ at the 10mm bolt just above the battery clamp, easy-peasy. If you ever in a situation and need to get around while you wait for a proper replacement, you can use a 30amp fuse inline between the battery clamp and the 10mm bolt above it.

[StereoInstaller1]

Hey Luke, isn't the fuse box run on the double wire that is attached to the battery clamp 10mm bolt, not the fusible link terminal? Thought the fusible link only ran the DME?

Anyways, don't cut anything, just see if you have 12+ at the 10mm bolt just above the battery clamp, easy-peasy. If you ever in a situation and need to get around while you wait for a proper replacement, you can use a 30amp fuse inline between the battery clamp and the 10mm bolt above it.

No and yes? Power for the DME comes from the main relay, main relay runs only the DME and fuel pump relay and all of the above comes from that secondary power wire...if your background is domestics, BMW stuff is clear as mud, I swear.

LOL.

That 10MM bolt is the other end of that fusible link'd wire and you most certainly can do it as described above.

[ForcedFirebird]

No and yes? Power for the DME comes from the main relay, main relay runs only the DME and fuel pump relay and all of the above comes from that secondary power wire...if your background is domestics, BMW stuff is clear as mud, I swear.

LOL.

That 10MM bolt is the other end of that fusible link'd wire and you most certainly can do it as described above.

:P

Just checked it. Power for fuse box has the double wire and connects to the back of the 0awg battery clamp, the fusible link only goes to the DME, like this link also repeats...

http://www.r3vlimited.com/board/showpost.php?p=3363042&postcount=2

There's 10 e30's here at the shop today, all the non-swapped cars are wired per the above link. Taking the fusible link off, still allows all accys to work, but the car won't start as the fusible link is what goes directly to the relay group and powers the main relay - DME gets no power.

EDIT: You post had me doubting my memory :/

[StereoInstaller1]

:P

Just checked it. Power for fuse box has the double wire and connects to the back of the 0awg battery clamp, the fusible link only goes to the DME, like this link also repeats...

http://www.r3vlimited.com/board/showpost.php?p=3363042&postcount=2

There's 10 e30's here at the shop today, all the non-swapped cars are wired per the above link. Taking the fusible link off, still allows all accys to work, but the car won't start as the fusible link is what goes directly to the relay group and powers the main relay - DME gets no power.

EDIT: You post had me doubting my memory :/

Huh...and yours, mine! I see exactly what you mean: the secondary power wire looks to connect to only the main relay input...well what the hell!

Now I wish I had an E30 around that wasn't in pieces...maybe my old one was wired wrong before I got it...but I have seen a half dozen that lost all power to everything when the fusible link went out...so WTF!

Looks like I am wrong on what all that fusible link runs.

[NorWest]

Here is an easy test for the fusible link: does anything work in your car aside from your starter?

If yes, its good.

If you car will only run the starter and NOTHING else works, its the fusible link.

Seriously, if your headlights, dashlights, radio, HVAC, domelights...if anything works at all, the fusible link is good, end of diagnostics.

Now, what to do if it is bad...personally, I replace them with "Mini-ANL" fuses. I like to use small fuseholders like this: http://www.ebay.com/itm/4-6-8-10-Gau...-/111009587537

Best of luck.

Luke

Boom end of diagnostics. everything works in my car my radio, headlights, domelights, HVAC it's all good I just can't get spark. I'm checking for a cracked distributor rotor tomorrow. Thanks for the help Luke! and yes I am very much a noob to BMW electrical stuff but someday i'll get there.

[ForcedFirebird]

Boom end of diagnostics. everything works in my car my radio, headlights, domelights, HVAC it's all good I just can't get spark. I'm checking for a cracked distributor rotor tomorrow. Thanks for the help Luke! and yes I am very much a noob to BMW electrical stuff but someday i'll get there.

Did you miss the rest of the posts? That quote is wrong. Only the ECU will be down if the fusible link is broken ;)

[StereoInstaller1]

Boom end of diagnostics. everything works in my car my radio, headlights, domelights, HVAC it's all good I just can't get spark. I'm checking for a cracked distributor rotor tomorrow. Thanks for the help Luke! and yes I am very much a noob to BMW electrical stuff but someday i'll get there.

OK, so that whole thing is wrong...but here is one: does your Check Engine light come on when you turn on your key? not talking about the big orange CHECK, but the smaller red square...I think it is on the left?