No power to chassis harness

[Moe steves]

In the process of ka swapping an 87 s12 engine is running but it appears that my chassis harness is not receiving power, as I have no power to the headlights turn signals etc. I was able to power the ecu by sending 12 volts to the engine management fuse in order to get the car running. How do I go about giving the chassis harness power. Any thoughts on what my issue could be?

[seishuku]

Fusible links, probably.
They're in a small rectangular box located behind the passenger (right) headlight, right near the battery.
They usually get crusty and the wire usually fails.

[Moe steves]

Connections have been snipped that feed power to the fusible links, I see a black and white wire, a green and red wire and a white wire, would I feed power to the black and white/ green and red and ground the white? Or feed power to them all

[seishuku]

Going off memory here, but as I recall:
Black and white is power feed to high current stuff to the engine (fuel injectors, coil(s), solenoids, etc).
White wire is power to and from alternator (to power car from and power to battery for charging).
Green I *think* is power to some of the chassis (blinkers/marker lights/etc, maybe?).
Red might be the rest of the chassis (headlights, dash, etc).

I would verify all that, but I can't seem to find my electrical diagrams, it's been awhile since I've needed them. lol

[Moe steves]

Thank you for the info! I sent power to those wires and it immediately blew one of the fusible links, should I run fused power to them? If so what amp?

[Moe steves]

got that replaced and it seems to be doing fine now, ecu has power without jumping it through the fuse box, I however still have no lights. Any idea what my issue may be?

[seishuku]

I mean, it's usually a pretty good idea to fuse anything power that goes to the battery. lol
This is the power diagram for a MK1 S12, but should be mostly the same on either MK1 or MK2:


As for the lights, for exterior lights it could be a bad stalk switch, they're known for poor reliability, so check that.
Interior lights, there's the extended storage switch that turns those off, that's *usually* attached to the fuse panel inside (passenger kick panel? I don't remember)

Otherwise, the heavy white wire is the main power feed to a lot of circuits in the car.

Here's the service manual for a MK1 S12 (86 and older): http://www.yariksteel.ru/manual/s12/s12_manual.pdf

Might help trace things out.

[Moe steves]

Thank you!

[weitrhino]

I would advise against using fuses in place of fusible links. Although both are circuit protection devices they work in different ways.

Fuses, of course, will blow when voltage or current exceeds their limit and that might just be for an instant. Fusible links on the other hand are heat-failure devices and usually don't fail all at once. They're just smaller gauge snips of wire at the start of the circuit (from the power source) and will fail under prolonged heating typically due to excessive current draw.

My sense is if you blew (a proper) fusible link right away then something is likely shorted in that circuit.