loweredd

iTrader: (2)

I'm working on hardwiring the LS1 harness this weekend. I have the relays and bases, I am headed out to pick up some Painless fuse blocks.

The 98 wiring pdf's I got show the fuses AFTER the relays......I want the fuses BEFORE the relays, correct? Fuse the wire coming in to the relay. The Air-Ride relays I got have the incoming wire fused........I guess it might not matter.

How did you guys do it?

leonpiper69

iTrader: (3)

i always fuse before a relay, that way if anyhting could ever short or go wrong its dead from the fuse forward.

loweredd

iTrader: (2)

Yeah, that's what I thought. If something goes, it will not take the relay....I suppose though, if it pulls too many amps through the relay BEFORE the fuse, could it take out the relay LIKE a fuse????? Hmmmmmmm.............

leonpiper69

iTrader: (3)

not really. the way i see it. its kinda like pulling the plug. if you fuse a crcuit at the very beginning you can do whatever you want down the line. like say its a 20 amp circuit you can put a 20 amp fuse in it and use a 30 amp relay. any parts of the circuit that are overkill are still going to be protected by whatever limit you set with your fuse.

G-Body

iTrader: (4)

I would prefer to fuse before the relays for that reason.......however I don`t really see a big difference. IIRC GM fuses after the relays anyway.

On my conversion I fused after the relays because it was the only way to get the proper size fuses. IE: the front and rear O2 sensors are run off the same 30A relay, The circuit branches after the relay to 2 15A fuses and then to the 02`s. same with the other relays (One powers the odd coils and injectors and the injectors and coils each have their own fuse after the relay.)

loweredd

iTrader: (2)

https://ls1tech.com/forums/showpost....82&postcount=5

I'm going off of Crisp3's diagrams here, they are after relays.....it looks like. G-body, looks like yours with the ign branched off 2 ways after the relay.

ryanvv355

iTrader: (17)

Fuses should be as close to the power source as possible. Over current through a relay could start it on fire in a worst case scenario, not good.

G-Body

iTrader: (4)

Yep, I wired it so that my circuits branch after the relay. Each relay powers 2-3 circuits. and each circuit is individually fused.

loweredd

iTrader: (2)

Ah yes, I am thinking of it wrong. With a relay, it would be the NEW power source, not the battery. My brain is gonna smoke. hehehehehe.

I guess that's fine, as long as it's not my wiring job.


BTW, I LOVE crimping metri-pack crimps. NICE. I used to love my Craftsman open barrel style crimpers, but these new connectors with the metri-pack style are just plain awesome.

TomH

iTrader: (1)

Ummm, you might want to fuse the circuit after the relay, since it's the high amperage side with the device that's actually drawing current; but that's just my opinion and I could be wrong.

Good luck.

ryanvv355

iTrader: (17)

The power source is always the battery or alternator, the relay is just the switching device

loweredd

iTrader: (2)

Well dang you two.......I guess it's gonna be a tug-of-war.

Ready


Set


GO!

TomH

iTrader: (1)

Yes, the battery is the source, but the relay adds an independent switching circuit (i.e. Path to ground) to the primary circuit. (The device is also grounded.)

This reason most high amp circuits ( e.g. Lights, starter, horn, etc.) require relays is to keep the current draw below the limits of the switch (i.e. Protect the switch.) Here's another logic test; let's say your headlamps spec a 20 amp fuse; fusing the switching to circuit will have no effect since the lamps are on the primary circuit. (i.e. With a 1.5 amp fuse on the switching side the lamps will run all day.) My advice would be to fuse (circuit breaker) the primary circuit, but as said before, that's just my opinion and I could be wrong.

Good luck.

loweredd

iTrader: (2)

OK, new question......on my switched wires to my 5 relays, can I chain one to the next? I am using my factory firewall junction, and will run a seperate constant for each relay, but I'm stuck on this....I know the switched portion of the circuit just turns the relay on, so it doesn't really need that much juice....a 14ga from one relay to the next with a wire off of the last one to the key switch?

Maybe I should go to bed for the night, and work on it in the morning. LOL.

TomH

iTrader: (1)

Try this link for relay wiring hints...

http://www.the12volt.com/relays/page5.asp

Good luck!

Rodder

iTrader: (2)

Daisy chaining will work fine for that and is a lot cleaner than making 4 splices or 1 huge splice.

loweredd

iTrader: (2)

Rodder, if I wouldn't have fallen asleep last night, I was just gonna go out and do that. LOL.

Do you think I would be OK to do that on the constant battery supply too? My thinking on that would be I should do each seperate becuase of the amp draw once the relay is in use.

stealth71

iTrader: (15)

Isn't each of the battery inputs to the relays going to be fused individually? Like 2 - 15 amp circuits for the INJ1/ING2.

I wired one large 8ga to a 6 port fuse block. Then each fused circuit leaves the fuse block to the specific relay.

Carshopinc.com

iTrader: (5)

All circuits are fused with either a fusible link or single inline fuse, A relay is a way of controlling a circuit remotely. Imagine if we had to run all large gauge wire to everything in the car, IE column, radio lights? Large power sources such as relay feeds should be battery protected with a fusible link or large maxi fuse...... Individual components after relays should also be fuse protected and circuit isolated when possible, by doing this it makes tracing a short alot easier by narrowing down the circuit/component failure....
Just a random thought from my half functioning brain today.....

loweredd

iTrader: (2)

I have them wired up except for the 12V constant supply TO the relay. I will run those through the stock firewall junction, and I was planning on sticking a few inline fuses in there. I fused all 7 circuits AFTER the relays, just like Crispy3's diagrams.

Heck, I ran the whole LT1 through just the key switch last time. No relays.