• If you currently own, previously owned or want to own an Avalanche, we welcome you to become a member today. Membership is FREE, register now!

Perplexing Electrical problem (melted ACC+ box & more)

IBMike

SM 2010
SM 2008
SM 2007
SM 2006
SM 2005
SM 2004
Full Member
Joined
Aug 22, 2004
Messages
2,765
Location
Peterson Air Force Base, Colorado
Been dealing with this problem for over a year now. Started pre-electrical system mods. Battery was not charging, and then my red acc+ box started melting. THen my fusible link finally melted through. I replaced it, and the battery. Seems like the problem went away for awhile, and then came back. My new Optima red top wouldn't hold a charge.

I replaced the alternator w/ a 145 amp (which would rule out the voltage regulator), and added the painless dual battery mod complete with Optima 2 yellow tops.  Didn't solve the problem, the nut in the acc+ box actually melted itself loose from the plastic. After the fusible link failed again, I upped the ante and replaced it with 4 guage, fused, and run straight to the battery.  Seemed to do the trick for a bit... but now I notice the once red 4 guage is now turing black at the edges and the fuse holder is getting too hot to touch when the truck is run for a couple minutes.

Cliff (I Change) and I spent a couple hours this weekend burning brain cells, but we couldn't determine the cause.  :E:

Anyone have any ideas? I need to get this problem solved before nationals... guess I'll have to take it in to the dealer before too long.

Thanks in advance for any words of wisdom.
 
You have huge amp draw

ever have starter checked?
 
ygmn said:
You have huge amp draw

ever have starter checked?


:E: Beat me too it....

Excessive load is what is melting the fusible link/wiring.... battery(unless shorted) or voltage will not do this...

Starter is the only large load on the truck that would overwhelm the fusible link ......
 
ygmn said:
You have huge amp draw

ever have starter checked?

I haven't. Cliff thought that might be the source. I guess I'll take it to the dealer and start there. I have just been hesitant to take it to the dealer because I don't know how they'll react to the dual battery, wondering if they'll even tackle trying to solve the problem. At least if I tell them to check the starter, they'll have a specific place to start.

Or, is this something I can just pull out myself and take it to a parts store and have them check?

 
FlaBouy said:
:E: Beat me too it....

Excessive load is what is melting the fusible link/wiring.... battery(unless shorted) or voltage will not do this...

Starter is the only large load on the truck that would overwhelm the fusible link ......

SOunds like we have a consensus... lol

Will work that angle and see if that does the trick.

Thanks!
 
local auto parts store should be able to test starter...

or get a ring type amp meter and put around battery cable and start truck...

Fusible links and large fuses are there to prevent forest fires under the hood of your truck...

if you increase their sizes... other wires will catch fire and well that is BAD...

 
All right, couldn't find anyone with a tester, so I just went ahead and got a new starter. Am searching the board for info on doing the job... being a non-motorhead, I figure I need all the help I can get. If anyone knows where a run-down of the job is, can you hook me up?

I've gotta make it to Steve & Holly's going away GTG at 3, so I can't do my usual making a 1 hour job take 3 hours.  :E:
 
i don't think it's the starter, if you follow the original positive cable it runs from the pos. post on the battery down to the red junction box and from there to the starter. in stock form your  fusible link melted, could've been resistance at the connection in the red box but you took that out of the equation by by-passing it.your "charge" cable now runs from the back of the alternator through a fuse and then to the pos. post on the battery.the starter does indeed draw alot of amperage but it's momentary,maybe 5 seconds,the starter current does not run through your "charge" cable,and the alternator has no output at engine cranking speed anyway,if your starter is drawing excessive current it would draw the battery down more than normal but your 145 amp alt. would still recharge it back up!!! here is my thinking,optimas have a higher charge acceptance,i think your charge cable AND fuse holder are too small,get a GOOD fuse holder like stinger etc. make it 200 amp,and change your charge cable to a minimum of 2 ga.      OR , PM SPERRY (y)
 
jimbo53188 said:
here is my thinking,optimas have a higher charge acceptance,i think your charge cable AND fuse holder are too small,get a GOOD fuse holder like stinger etc. make it 200 amp,and change your charge cable to a minimum of 2 ga.? ? ? ?OR , PM SPERRY (y)

THe problem was occuring pre-optima & pre-145A alt.

I do have a Stinger fuse holder & fuse, but only went with 4 ga.

I wsa wondering about it being the starter, as the wires heat up after the truck is running for 5 min or so and stay hot...  :E:
 
Did you check for the mentioned resistive connection?

Fusible links are simply just a (usually finely) stranded wire within flameproof silicone insulation. GM simply crimps them. The fusible part shouldn't be much longer than 9". Then it crimps to a larger, longer section (length to fit) in some cases - just not the stock alternator. Is the link becoming hot? When? Charging or cranking. It should not be part of the cranking current flow.

If you have a higher output alternator, did you size the link accordingly?

Can you obtain a clamp-on DC Ammeter? Fry's has a good one, among a few.

Is the crimp on the lug connecting to the link secure and clean? Lug and surface clean? Nut tight?

Same for the battery and starter cable lugs. Clean cable, crimp surface and the mating surface to the connector lug clean?

As somewhat mentioned prior, if the box is melting from heat by electrical, it is resistive connections in the area or a hell of a lot of current! If it were cabling, it would be along the length of such cable(s), except where heat would otherwise be dissipated.
 
IB Mike said:
THe problem was occuring pre-optima & pre-145A alt.

I do have a Stinger fuse holder & fuse, but only went with 4 ga.

I wsa wondering about it being the starter, as the wires heat up after the truck is running for 5 min or so and stay hot...? :E:
i still don't think it's the starter,it's draw is momentary(only to start the engine) put a volt meter on the battery posts when it's running,should be 13.0-15.0 volts,the heat in the cable is from resistance,forcing too much amperage through too small of a wire,or the alt is going,not unusual in multi batt app's,two or more batt's are twice the load. you're using the painless dual batt system,are you draining one battery down and then switching it "online" to charge it back up? ?stock alternators are not designed to charge dead batteries,only replace 5% or so discharge,stock alt's will not run at 100% capacity for long , 80% at best, upgrade your charge cable to 2ga iminimun and use at least a 200 amp fuse and remember every additional connection or splice adds more resistance and more heat,and it's a catch 22=the more resistance the more heat produced and as temps rise so does the reistance :eek:  i have a 275 amp alt,my charge cable is 2/0 ga.from tha batt + to the back of the alt,mechanical crimped copper lugs,soldered as well and sealed with epoxy filled heat shrink and fused with 2x200 amp fuses
 
Yes, a starter's current draw should be as brief as it's operation. My starter won't even trip a 150 Amp breaker! An 8.1 may, but "just".
 
sperry said:
Yes, a starter's current draw should be as brief as it's operation. My starter won't even trip a 150 Amp breaker! An 8.1 may, but "just".
the 8.1 starter is a "permanent magnet" style,it's draws only about 100 amps,
 
Of course, dependant on the load (temp and such).

I should measure mine with my clamp-on (peak hold). Then pull a PCM fuse and look at the starter current as it's cranking a bit and average it.

Then do that on an 8.1. "Normal" crank current would be better known then.
 
So neither of you guys have ever had a starter solenoid hang up on ya?? How about a short to case in the starter motor windings? (not direct short--just one of those nagging high resistive types...)

My thought process is centered around the only system in the truck that can draw enough amperage to melt a #4 cable....I run a painless kit with my two batteries and have for over a year...no browning of any cables even though the fusible link and battery cable are still stock...

I will say my 180A aftermarket battery shorted and drew the battery down, but even with that the wires were fine... Even though you have a 180A alternater doesn't mean you are drawing 180A.... :wave: I find it hard to accept that the stock 105A alternator with stock cabling and fusible link (which is where the problem first showed it's head) can melt the primary wire and fusible link.. I would think the regulator on the back of the alternator would die first....

Ohm's law teaches us that heat is generated by resistance (small wire or loose connection) and the wire properties are tested at a given temperature and sized according to the resistive value measured at a given length. It is load (amperage) that dictates how much heat is given off by the wire....

If the battery is not shorted, or have a dead cell, I would think the starter to be the only other system on our trucks that can draw that kind of amperage to melt cables and fusible links over time... (systems from the factory are the only ones considered here..)

Not saying the starter is the issue.. just a very good place to start.... :wave:
 
he states that the charge cable from bat to alt is hot,starter doesn't draw current through that cable, besides if the starter sol or short in armature were the culprit,those would be constant and kill the batt when trucks not running.
 
jimbo53188 said:
he states that the charge cable from bat to alt is hot,starter doesn't draw current through that cable, besides if the starter sol or short in armature were the culprit,those would be constant and kill the batt when trucks not running.


Hmmm...not quite sure how your truck is wired but the little red acc+ box that he indicated was melting in post number one catches the alternator output? and then goes in two directions... first the battery.... secondly the starter. The starter solenoid comes from the underhood fuse block and is controlled by the starter relay...Since the engine is not turning, there is no alternator output during cranking operations, so the wire from the battery to the red block and then to the starter is used for 12V to the starter... once the engine cranks, and starter is disengaged, the PCM outputs a field charge to the alternator regulator that then outputs charge voltage back to the battery from the altenator output to the red box and then from the box to the battery....

If the starter motor had a high resistance ground to case, it would cause excessive current when the starter was cranking since that is the only time voltage hits the starter motor. Since the relay would then release when engine was started, solenoid would disengage and starter motor would lose 12V.... there would be no current draw when the starter relay did not activate the starter solenoid, so no draw down of the battery would take place...

What would happen though, is high current would take place during normal starting conditions, which could, if high enough, produce enough heat to start melting insulation, connectors, etc.... especially during the winter months where cranking times might be effected...think of a heating element when voltage is applied... it gradually builds a red fiery glow.... same here with high current under short duration.... If done enough, that cycle over time would show exactly the symptoms described....

So yes, a starter can cause this without drawing down a battery...? :wave:

BTW, the starter relay is fed by a 40A fuse which should clue one in to knowing it is the solenoid being controlled by the relay.... it closes a set of solenoid contacts that are rated for the amperage being drawn by the starter motor....

Enough theory.... get that starter checked..... >:D
 
. After the fusible link failed again, I upped the ante and replaced it with 4 guage, fused, and run straight to the battery.? Seemed to do the trick for a bit... but now I notice the once red 4 guage is now turing black at the edges and the fuse holder is getting too hot to touch when the truck is run for a couple minutes.
[/quote? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?in this case he clearly replaced the cable from alt to red box,with one going from alt to bat positive,that cable is the one heating up, and is no longer tied in with the starter cable,the original bat cable now runs from bat positive down to red box and then to starter,that cable is live 12 volts constantly , now as far as the cable from the alt to the battery positive, the one thats heating up and black at the edges with the fuse holder too hot to touch,my guess is he's got a very capable 145 amp alt.feeding 2 optimas,optimas capable of higher charge rates,and that 4 ga. cable is TOO SMALL!!!! upgrading to at least 2ga.and a HD fuse holder will cure it.
 
jimbo53188 said:
. After the fusible link failed again, I upped the ante and replaced it with 4 guage, fused, and run straight to the battery.? Seemed to do the trick for a bit... but now I notice the once red 4 guage is now turing black at the edges and the fuse holder is getting too hot to touch when the truck is run for a couple minutes.
[/quote? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?in this case he clearly replaced the cable from alt to red box,with one going from alt to bat positive,that cable is the one heating up, and is no longer tied in with the starter cable,the original bat cable now runs from bat positive down to red box and then to starter,that cable is live 12 volts constantly , now as far as the cable from the alt to the battery positive, the one thats heating up and black at the edges with the fuse holder too hot to touch,my guess is he's got a very capable 145 amp alt.feeding 2 optimas,optimas capable of higher charge rates,and that 4 ga. cable is TOO SMALL!!!! upgrading to at least 2ga.and a HD fuse holder will cure it.


Not to be one to argue..... :D

It melted everything prior to doing all the dual battery upgrades, bypasses, unfusible links....

and I was mainly poking fun at the starter short causing battery draw down issue anyway.. that was most definitely an error in thought process..... >:D

:kidding:

Just trying to giver suggestions... not beating on anyone here..... :love:
 
Mike,
Just curious how this is doing... Did you get your battery replaced?

We replaced the cables in South Dakota. This system under its highest load was about 70 amps (after replacing cables/checking all connections). Normal was well under 60 amps with all lights and amplifiers off.

Keep me posted of your progress... Keep a close watch on it to see if it rears its ugly head...
 
sparqui said:
Mike,
Just curious how this is doing... Did you get your battery replaced?

We replaced the cables in South Dakota. This system under its highest load was about 70 amps (after replacing cables/checking all connections). Normal was well under 60 amps with all lights and amplifiers off.

Keep me posted of your progress... Keep a close watch on it to see if it rears its ugly head...

Of course I haven't found time to get a new battery... still catching up from being on vacation... lol

I did find the receipt, I bought in in Nov, so I should be good to go under warrenty.

I have been checking the cables and they don't appear to have been getting hot, so maybe it was the loose terminal that was causing the issue.

THanks again for your assistance... sorry it actually did turn into midnight maintenance... lol
 
Back
Top