1990 Suburban ECM-1 fuse blows, again & again :-(

[89Suburban]

Never mind, that is the pink wire feeding that fuse.

 

[MrMarty51]

Well then, could it possibly be a problem in the alternator ????

 

[89Suburban]

Ok, here is the back of the ECM fuse, one pink wire feeding, 2 pink/black coming out:

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One of the pink/black wires goes about 10" then doubles back 10" to the bulkhead connector at this position:

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The other pink/black wire goes 20" to this plug: Yes, that is my blood on the wire.

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There is a black ground wire in that plug, and also there is a brown wire that tuns to this connector, which I believe connect to the ECM?

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[89Suburban]

Confirmed there is 2 pink black wires coming out of the bulkhead connector into the engine harness and one does go to the alternator, I am assuming that is the trigger wire to have the alternator charge after the key is turned on.

The other pink/black runs all the way around the harness to the area of the front pass side valve cover area to a splice. I measure that splice as to being approx 17" upstream of the injector connectors. Pic:

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From that splice, 1 each of red and white wires run to the 2 injector plugs, 1 pink/black to the ESC Hybrid Function?(#8 in the next pic), 1 pink/black to the EGR soleniod, and 1 pink/black runs through the pass side ECM harness grommet to the ECM.

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I am lost what those white and black connectors noted above plug into.

 

[Jims86]

There is also a pink/blk wire running to the AIR diverter, if she has it...but even if she does not have AIR, the pigtail for it is still there, and that wire could be running close to something hot, and could possibly be shorting out.

 

[89Suburban]

So in a nutshell, I would disconnect the ECM, the ESC Hybrid whatchyamacallit, that white connector (I am assuming that might be a brake switch or sumptin?), and that black plug whatever the hell that is, should be under the dash in the area of the ECM/glovebox, unplug the the alternator, unplug the EGR solenoid, and unplug the 2 injector plugs. Then put a fuse in and if it blows it again, you definitely have a short somewhere in that pathway.

 

[89Suburban]

There is also a pink/blk wire running to the AIR diverter, if she has it...but even if she does not have AIR, the pigtail for it is still there, and that wire could be running close to something hot, and could possibly be shorting out.

I don't see that in my harness. Where would it be located? Oh and uh, Hi Jim!

 

[Jims86]

I don't see that in my harness. Where would it be located? Oh and uh, Hi Jim!

Hey bud...it should be over on the pass side alternator area. might be hidden, or even taped up....hopefully. Heck, i would even go out and unplug the alternator, then see if it blows the fuse....There have been a few fuse blowing alternator issues the last year or so.

 

[CWGRL]

ok Boys....

I unplugged alternator, kick down, and every pink/black wire under the dash...

It still blows!

I really do appreciate everyone help!

 

[MrMarty51]

I think there are a couple of modules behind the dash, maybe try unplugging them, one at a time and see if it still blows the fuse.
Could unplug all two or three of them then check it.

 

[CWGRL]

Ops! Sorry for the double post... Think my brain is on maximum overload... LOL

I'm tempted to just throw a large amp fuse in, start it, and follow the smoke! LOL

 

[89Suburban]

1990 Suburban ECM-1 fuse blows, again & again :-(

GAWD damn it!!!!!

I wish I could help.


Posted from hell

 

[Jims86]

I think there are a couple of modules behind the dash, maybe try unplugging them, one at a time and see if it still blows the fuse.
Could unplug all two or three of them then check it.

No, the ecm is pretty much stand alone on that fuse, I think she may have a chaffing wire issue...question is, where. I wish she wasnt so far down I-5, I would go yank the harness and figure it out.
Oh, another thing to unplug.....the trans connector for converter lockup, or at least check those wires. Remember when your world went dark when trying to test the TCC , John?

 

[HotRodPC]

No, the ecm is pretty much stand alone on that fuse, I think she may have a chaffing wire issue...question is, where. I wish she wasnt so far down I-5, I would go yank the harness and figure it out.
Oh, another thing to unplug.....the trans connector for converter lockup, or at least check those wires. Remember when your world went dark when trying to test the TCC , John?

Either that, or how about a defuctive ECM? Something on board got hot, melted some pins causing a direct dead short. ? ?

 

[Jims86]

That is possible.