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

[CWGRL]

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You mean that stuff don't work or it's unhooked?

I unplugged everything... LOL

Thanks for all your help!

 

[89Suburban]

Another question, is there a trailer brake controller wired into the vehicle?

 

[CWGRL]

Another question, is there a trailer brake controller wired into the vehicle?

negative

 

[CWGRL]

Question.... is the main source of power to the fuse panel come from the harness in the engine compartment?

 

[foamypirate]

There should be two, one from alternator, and one from the starter.

 

[HotRodPC]

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You mean that stuff don't work or it's unhooked?

Here is a pic of my mystery fuse, it has a 3 amp fuse in it, Retro took a high heel to my nuts and said it's for the starter circuit in my build thread.

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So right there is something strange, yours is 30 amp fuse and mine is 3 amp, maybe a clue? I don't recall seeing that in my '89 harness but after I finish up my breakfast here I will go check it out.

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So then we just need to figure out what both your Burbs have in common to figure it out that most other squares don't have. How about Power Mirrors?

 

[Jims86]

sorrybto beat adead horse, but did you unplug both injectors too?

 

[CWGRL]

sorry to beat a dead horse, but did you unplug both injectors too?

I was able to get the truck in the backyard, paid tow co. $80

as of this moment here is what is unplugged.

Injectors, Map, IAC, EGR solenoid, ESC, ECM, O2, Tranny, Fuel pump, relays, oil pressure sending unit, TPS, Coolant temp gauge, no radio, no dome lights, dash gauges completely unplugged, alternator, kickdown switch, and any pink/blk plug under dash.

I also removed distributor, and coil. check harness against firewall, all looks good.

Still blows fuse! Maybe, fuse panel?

I borrowed a Power Probe from a friend but at this point, I have no idea where to start probing! LMAO

 

[RetroC10Sport]

At this point, a chafed wire that's dead shorting on some metal is the most likely culprit. Check where the ECM wiring passes through the firewall at the rubber grommet.

That fuse holder is supposed to have a 3 amp, not a 30 amp so something there is wonky as well.

 

[CWGRL]

That fuse holder is supposed to have a 3 amp, not a 30 amp so something there is wonky as well.

I agree, I did replace with 3amp

 

[HotRodPC]

At this point, a chafed wire that's dead shorting on some metal is the most likely culprit. Check where the ECM wiring passes through the firewall at the rubber grommet.

That fuse holder is supposed to have a 3 amp, not a 30 amp so something there is wonky as well.

Wonky???

 

[RetroC10Sport]

Yeah, wonky...Ya Okie...

 

[MrMarty51]

There is a whole mess of wires, I`ma thinking, that is run through brackets behind the heads, theys a real sunnygun to get to, maby something along there ???
Fuel pump wire, all alng the frame rail ???
fuel pump itself ???

 

[Jims86]

Check behind the glove box under th ecm....sometimes the harness comes loose, and lays on the temp cotrol cable, and wears through the harness.

 

[HotRodPC]

Yeah, wonky...Ya Okie...

Don't forget, I'm from So Cali. Guess not redneck enough to understand wonky.