Fuse box Power without ECM?

[Trainuy995]

Asking for a friend who I’m trying to help - he has an 89 k1500 that he’s currently installing a bored out 454 out of a 73 with a Holley 650 sniper and hyperspark kit. He’s struggling to get power to the fuse box without an ecm, he said he tried power to the red wire and grounding the black but he got nothing. I don’t know much about it but I told him I’d ask around. Any help appreciated, or even somebody who’s done something similar who I could get him into contact with

 

[PlayingWithTBI]

He’s struggling to get power to the fuse box without an ecm, he said he tried power to the red wire and grounding the black but he got nothing.

The ECM shouldn't have anything to do with power to the fuse box. There's a hot wire going from the battery to the power distribution block on the passenger side firewall, then a hot wire going to the fuse block from there. Both wires have a fusible link in them.

 

[Schurkey]

Download the '89 service manuals from the links located on this web site. The wiring diagrams are in there.

 

[PlayingWithTBI]

Download the '89 service manuals from the links located on this web site. The wiring diagrams are in there.

I just happen to have it bookmarked, here ya go.

www.gmt400.com/threads/88-98-service-manuals.43575/

88-98 Service Manuals

Over the years I have collected a bunch of GM service literature. Links to PDF Scans of service and STG manuals and a links to the Parts manuals. You'll need the FREE Adobe Acrobat reader to open these files. Get it directly from Adobe here {http://get.adobe.com/reader/} If you're not...

www.gmt400.com

 

[618 Syndicate]

The ECM shouldn't have anything to do with power to the fuse box. There's a hot wire going from the battery to the power distribution block on the passenger side firewall, then a hot wire going to the fuse block from there. Both wires have a fusible link in them.

Battery, alternator, distribution block/starter if I'm remembering correctly.

 

[PlayingWithTBI]

Battery, alternator, distribution block/starter if I'm remembering correctly.

I'm not sure what you're saying but, I'll try. There's 2 positive wires from the battery, one to the Distribution Block which has a Fusible Link, the other (the bigger one) to the starter doesn't have one, gotta be careful with that. The alternator goes to the DB and has a FL. All other ones should have a FL.

Here's a pic of my 88's block, when I was documenting my AC wiring. Note, the connector on top of the big harness in the background is for my WBO2 so, disregard that one, ha ha. You can still see all the FLs coming off this DB. Yeah, it is a mess which makes it hard to trace wires but, it can be done

You must be registered for see images attach

 

[618 Syndicate]

I'm not sure what you're saying but, I'll try. There's 2 positive wires from the battery, one to the Distribution Block which has a Fusible Link, the other (the bigger one) to the starter doesn't have one, gotta be careful with that. The alternator goes to the DB and has a FL. All other ones should have a FL.

Here's a pic of my 88's block, when I was documenting my AC wiring. Note, the connector on top of the big harness in the background is for my WBO2 so, disregard that one, ha ha. You can still see all the FLs coming off this DB. Yeah, it is a mess which makes it hard to trace wires but, it can be done

You must be registered for see images attach

Maybe the earlier trucks are different, but on my 98 the power went from the battery to the alternator, from there one wire went to the starter, and another to the distribution block.
I landed straight on the starter from the battery, and then to the alternator and from there to the distribution block when I relocated the battery under the bed.

 

[Komet]

Factory TBI trucks don't need an ecm to power the rest of the vehicle. There's one big red wire that crosses over to the fuse panel area and powers most of that, also a few others that come out the passenger side. I think one of them is the hvac panel power. Not sure if this picture helps but it's what a minimum functional setup looks like:

You must be registered for see images attach

There's no avoiding spending time with the factory service manual wiring diagrams when you're doing custom work.

 

[Trainuy995]

The ECM shouldn't have anything to do with power to the fuse box. There's a hot wire going from the battery to the power distribution block on the passenger side firewall, then a hot wire going to the fuse block from there. Both wires have a fusible link in them.

I sent him this and a wiring diagram so we’ll see what he does with that I suppose, thanks for the help

Maybe the earlier trucks are different, but on my 98 the power went from the battery to the alternator, from there one wire went to the starter, and another to the distribution block.
I landed straight on the starter from the battery, and then to the alternator and from there to the distribution block when I relocated the battery under the bed.

Thanks for the info I’ll send him this too

 

[PlayingWithTBI]

Maybe the earlier trucks are different, but on my 98 the power went from the battery to the alternator, from there one wire went to the starter, and another to the distribution block.

Yeah, Vortecs are different. You also have a fuse box under the hood. TBIs only have the one under the dash near the e-brake.