Fuseable Link (Update 9/8/11)

[1971SE440]

I was driving my car down the freeway and turned on the blower vent gave the car some gas and everything went dead. After waiting 1.5 hours for a flat bed wrecker in 107 degree heat I got it towed home. I noticed the fuseable link was burned. I purchased a new one and connected the battery and it went up in smoke (quickest $20 bucks I ever spent). This was with no key in. I checked the wire from the fuseable link to the firewall connection and it looks good. Any ideas. I made a make shift fuseable link and every time I give it battery power the starter relay sparks and I disconnect. I even put a new relay in (from local parts house) and same results. Any ideas where to start? Its a 1971 Charger. Thank.

[dodgechar]

  Dont know whats up there , but if you do search, fuseable link, there's some , mybee can help there.    good luck

[Chryco Psycho]

basically start by diconnecting circuits unti the short goes away , once you know the are to look at then start inspecting that circuit end to end

[1971SE440]

I looked under the dash and the 8 pin connection has 2 burned connectors. The black wire (acc wire) and the red wire (batt) are burned. Everything else looks good under the dash and under the hood. I removed the cluster so I could look at the battery gauge and it looks good with no burn't spots. I did have a intermittent problem when I got my aftermarket radio installed. Sometime when I would turn on the fan blower the radio would short out. Once I turned the blower off the radio came on.  Does any one know where I can get a new 8 pin connector? Thanks.

[Chryco Psycho]

Typical , when you put it back together use some di-electric grease& coat the terminal so they do not corrode again & build up resistance / heat

[1971SE440]

Made new connections and got rid of the 8 pin connector. I put a fuse holder in line where the fuseable link goes right after the starter relay...to do some testing and it keeps blowing a 20 amp fuse. This is with the key off. Not sure where to look next. It has to be something that gets power with the key off.

[solids0be]

Dont use a inline fuse box, I tired the same thing and it ended up causing me more trouble then it was worth, burned out my ECU in my Dizzy trying to make it work. Track down the cause of the short in your system and then replace with a new fusible link with the correct gauge.

You obviously have a short that is seperate from the ignition switch so the first place id look would be at the battery, alternator, voltage regulator and all your grounds. Check to make sure no wires got burned up on your exaust and any accesories that may be linked directly to the battery like aftermarket radios.

[1971SE440]

I disconnected the alternator and the fuseable link did not melt. Took the alternator to the auto parts and it failed the test. Would not even start to run the pulley. Do you guys think that was the problem because everything works without the alternator hooked up or is there another problem that may have shorted this alternator? All the wires look to be in very good condition and the back of the amp gauge looks almost new. I have had this alternator for about 5 years on the car. Cheap one from local auto parts but it did have a lifetime warranty.

[Chryco Psycho]

Typically an alternator will not draw significant current & if it shorts internally will either quit charging or overcharge but I have not seen a case where the alt will short & blow a fusable link , but if you alt was siezed it mayhave caused the problem if everything seems to work ok without  the alt you may be ok

[solids0be]

When all my stuff Burnt up, it started with the alternator. Alternator failed AND started to overcharge, voltage regulator went, ate the fusible link, Tried to replace with an inline fuse,(Bad idea) shorted out my ECU, killed my instrument voltage regulator...Big ass head ache. Ive spent around $450 bucks to replace all the electronics/wiring the alternator/regulator took out.

Have the auto store test the alternator you buy before you take it home. I bought one from orielys took it home and tried it...still over charging...I troubleshot for a week before taking it back..it was no good...along with the 5 others they had in stock that I had them test. Ended up getting a Autozone alternator which is charging perfect.

[StevieRT]

Did you ever figure out the issue with this? My brothers 70 Charger is doing the exact same thing and I can seem to track it down. Everything behind the dash looks good too. I'm starting to wonder if its the ammeter, even though it looks fine. I might do the bypass trick to see if that works, otherwise I'm at a loss.

[nascarxx29]

If the amp gauge is acting up reach behind cluster and feel the Red & Black connections and wiring to see if they feel hot.Worse case amp gauge blows the fusible link if its not hard wired

[b5blue]

To both of you. You have a "short" somewhere. Disconnect the battery and use a meter set on "OHMs". Go to your fuse panel and pull the fuses. On the HOT or supply side of your fuse block test for "continuity to ground" by having one lead on a known ground source (Like the dash frame.) and touching the other lead to each fuse clip. One or more will give a reading, if they all do go to the main supply wire. If only one reads to ground (This is chassis ground, not battery ground itself.) that is the culprit. Tell me what you find! 

[nascarxx29]

Ive used 12 volt testlight in series with pos cable .With everthing off .If light is very bright pull fuses to isolate circuit.Or you got a dead short to ground non fused issue

[b5blue]

  Yes buy pulling all fuses you avoid back feeding ground through light bulbs or anything else. The short is most likely prior to fuse block or they would have blown fuses not a fuseable link. Checking the ignition switch plug from the harness for grounding (With the fuses out.) may help locate where the short is also.

[StevieRT]

Thanks for the help guys. I have gone through all of the car with my meter and with all the fuses pulled and the 3 plugs pulled of the junction block I am getting a short in the ign1 feed that goes from alt/volt reg/ etc. The weird thing is that its also shorted in the interior of the car, even with the plugs pulled. Is this correct? Thanks for any input.

[StevieRT]

I reread my last post and realized I wasn't very clear. Is the ignition 1 circuit as lables in the service manual a ground feed? I know it hooks up to the field posts on the alternator and then goes to the voltage regulator and ballast resistor, etc. Another thing, when the problem first started, we were trying to jump start the car with a battery jump pack, when the fusible link went suddenly. I replaced the fusible link and charged the battery normally, then it worked fine. Now all is dead to no avail. Could this be the voltage regulator? Could it cause a short? I have looked over all the wiring in the car and cant find a single real problem. Anyone have experience? Thanks in advance.

[b5blue]

At this point I would PM Dr. Nacho!  (I have a 70.)

[68neverlate]

I disconnected the alternator and the fuseable link did not melt. Took the alternator to the auto parts and it failed the test. Would not even start to run the pulley. Do you guys think that was the problem because everything works without the alternator hooked up or is there another problem that may have shorted this alternator? All the wires look to be in very good condition and the back of the amp gauge looks almost new. I have had this alternator for about 5 years on the car. Cheap one from local auto parts but it did have a lifetime warranty.

It depends on the kind of "internal" short in the alternator.  If the short is between the stator windings and ground, then it could cause a dead short from the battery through the fusible link, through the firewall, through the two connectors on the 8 pin connector that you previously showed, through the ammeter and back out the firewall to the shorted alternator.  The fusible link blowing likely saved your ammeter.  Curious... did the new alternator fixed the problem?     

[68neverlate]

I reread my last post and realized I wasn't very clear. Is the ignition 1 circuit as lables in the service manual a ground feed? I know it hooks up to the field posts on the alternator and then goes to the voltage regulator and ballast resistor, etc. Another thing, when the problem first started, we were trying to jump start the car with a battery jump pack, when the fusible link went suddenly. I replaced the fusible link and charged the battery normally, then it worked fine. Now all is dead to no avail. Could this be the voltage regulator? Could it cause a short? I have looked over all the wiring in the car and cant find a single real problem. Anyone have experience? Thanks in advance.

Were you able to isolate the problem? 

[StevieRT]

Yes I just figured the issue out! It was the main battery feed wire where it goes up the steering column to the ignition switch. It was tricky to diagnose when I was checking for continuity because everytime i would touch or pull on the wire it would 'unground' and leave me looking, once i finally dropped the column and pulled it apart I found it and fixed the stripped wire, everything is back to normal now. Thank you for the help guys!

[68neverlate]

Disconnect the battery and use a meter set on "OHMs". Go to your fuse panel and pull the fuses. On the HOT or supply side of your fuse block test for "continuity to ground" by having one lead on a known ground source (Like the dash frame.) and touching the other lead to each fuse clip. One or more will give a reading...

I did this just before getting ready to fire up my car after doing some wiring modifications (from my ammeter out to both the battery and the alternator).  I received partical continuity readings on three of the six circuits (supply sides).  Are those the readings I should see??     

[b5blue]

I'm not getting what you mean by "partical" ? 

[68neverlate]

Ooops... meant to say "partial".  I get a reading on the multimeter for the three circuits, but it's not full continuity.  Needle deflects 1/3 and 2/3 of the way over the span of the scale.  As if there's some resistance between the fuse box and full ground.  I'm just not sure if that's what I should see on those when doing that. 

The car was running with no noticable issues before doing my wiring mods... I just don't know if that's how they looked before starting the mods because I never thought to do that test then...