Wiring woes - RB25 in S14

[skazat]

So Im having an issue with the relay pictured below. I know its not the relay itself but must be in the wiring somewhere. Im hoping someone can help me out.

Basically from what I understand, the low side of the relay should make a connection when the ignition is put in the "ON" position, which in turn makes the high side come on.

Whats going on is the low side isnt making the connection so then the high side wont close the circuit, and it wont feed power to the ecu so the car wont turn on. What Ive been doing in the mean time is just manually closing the high side circuit by just putting a wire in between the terminals and it lets me turn the car on like it should. Because of that I know that the wiring for the high side is good theres just some kind of issue with the low side.

From what Ive figured out, theres a ground for both the high and low side so what Im left with is figuring out where the 'hot' wire is supposed to come from for the low side.

Heres the picture of the relay harness

[ze12o]

do you get a 12v when the ign is on?

[skazat]

12v where? on the lowside?

[ze12o]

well anywhere. there should be two 12v wires one constant and one when the ign is on.

[skazat]

right i know that. the low side should come on with ignition while the highside is constant 12v.

[ze12o]

well if its like any regular relay there should be
1 ground
1 constant 12v
1 switch 12v (ign on)
1 receiving 12v which goes to where you want power when the ign is on..

Do you hear/feel the relay click on when the ignition is on?

[skazat]

ok so what ive figured out is that theres one constant 12v going to the relay that is then split into both the low and the high side of the relay. which leads me to believe there has to be some other relay that grounds this one whenever ignition is on. ???

[ze12o]

well what is this relay specifically for?

[skazat]

I guess it turns on the ecu. the low side ground goes to PIN#16 on the ecu. I have an AEM EMS and the manual says that PIN#16 is the 'ECM Self-Shutoff Power Source'. Then the high side of the relay goes to PIN# 109,49,59

[Brok3n_RB25]

That would be your ECCS relay. The ground side is ECU controlled at pin 16.
That ECU pin controls the ignition relay also.
Check for continuity from the ground side of the relay coil to ECU pin 16. I'm betting that you have an open somewhere between there.

[ze12o]

Sorry i'm not too sure how that works without some sort of diagram... Try another relay.

[krappy]

both reds should be 12v into the relay, the black/white goes to the ecu and is ecu power, and the red/black should go to the ecu which i believe is the relay trigger.

[krappy]

and yes that is your eccs relay

[skazat]

Ive tried another relay so I know its not the relay.

@Brok3n so what your saying is there should be continuity between PIN#16 and the ground side of the Coil Relay? If theres an open in the circuit somewhere around there wouldnt the car still not run even with me jumping the ECCS relay?

[Brok3n_RB25]

Oops, didn't read.

Anyways, chances are you have a broken wire between the relay coil ground and the oem splice where the IGN relay tee's into ECU pin 16. Mine was an orange wire. It was spliced with a metal crimp.

[skazat]

yeah ive tried different relays.

[Brok3n_RB25]

Reread my post real quick. I edited it right after you replied. I didn't read all of what you posted.
Basically that relay is off of a splice that goes to pin 16. If the ECCS relay section of the splice is broken, then it will run when you jump the high side of the relay.
This means that your IGN relay has to still be connected properly if you're only jumping the one relay. You need both of said relays to run the car.

[skazat]

so are you saying that the wire running between the Coil relay and ECCS relay maybe broken? or that the wire running between the Coil relay and the IGN relay maybe broken?

[Brok3n_RB25]

Ok, I should have worded that a little differently.
The relay that isn't working isn't getting a relay coil ground signal from the ECU.
Since your IGN relay IS getting a ground signal still it's still wired to the ECU at pin 16.
This means that your ECCS relay (the one you're having problems with) isn't connected to ECU pin 16, by some means. Most likely a broken wire.
Trace the relay coil ground of your ECCS relay (the one that's not working).
I'd be willing to bet you find your culprit.

[skazat]

alright so if i understood correctly this time :P i should be checking the wire from the ECCS relay harness to ECU pin 16, correct?

if so I just checked for continuity between both points and its making a connection.
really thats why this is leaving me so confused. Im getting 12v at the lowside of the relay and im getting continuity between the ground side and the ecu so why wouldnt it be closing the circuit in the relay?

[Brok3n_RB25]

Ok. So correct me if I'm wrong here.
1) The relay coil ground has continuity to pin 16 on the ECU.
2) The relay coil has 12v to it.
3) The common pin on the relay has 12v of power to it.
4) When you jump the two high circuit wires together it works fine.

Can you hear the relay clicking?
If you can, are you sure the high side circuit (ECU power) is wired to the right socket on the relay base? The same goes for the relay coil power. Is it in the right socket on the base?
If you can't, then you must not have power to the relay coil side of the circuit.

Basically, there has to be a wire mixed up somewhere on that relay for it not to function properly. You might have to look at the relay itself to figure out which pins are which.

[skazat]

1. Correct
2. Correct
3. Correct
4. Correct

As far as my understanding of the relay works as long as the low side wires are on the low side it should work correctly, it doesnt matter what wire is on what terminal, and the same goes for the high side. And as far as that goes all those are right.

Let me ask you this. should I see continuity between ECU pin 16 and chassis ground? Thats what I thought and I think that the problem might lie there.

What confuses me though is that if the Coil relay shares the same ground as the ECCS relay why do I only need to jump the ECCS relay UNLESS.. the wire between ECU pin 16/ECCS low side ground and the Coil relay is broken. Hmm... get back to me on your thought. and btw thanks alot for the help

[Brok3n_RB25]

You definitely shouldn't see continuity from pin 16 to ground. That's an ECU controlled ground signal.

I'm thinking you're right about the wire between ECU pin 16 and the relay coil. I thought you said the relay coil ground did have continuity to pin 16, though?

[skazat]

Just so were on the same page, the ECCS relay is the blue one and the Coil relay is the brown one, right?

If so the only place Ive checked continuity to ECU pin 16 is from the ECCS relay.

This is a diagram Ive been referencing.

[skazat]

after looking at the diagram I think I should check for voltage at ECU pin 45 with the ignition in the on position.

[Boostin240sx]

Yes you are correct, check 45. Basically the way is works is 45 gives the ECU 12V then Pin 16 grounds the ECCS and Igntion coil. When you turn the ignition off the ECU also delays the ECCS turning off where in the case of a power FC is required to save. I had an issue where pin 16 from the power FC would never ground the relay so I put it on a switch and problem solved. Been DDing it that way since April just don't forget to switch it off.

[skazat]

Boostin, thats what my last resort is gonna be if I cant figure it out. Just put a switch on the ground for the ECCS relay. But Id like to keep it as simple as possible and have it turn on the way its supposed to.

[Brok3n_RB25]

I think you're easiest bet is going to be to find you're ignition switch signal wire at your dash connector and tap into that wire for pin 45.
It might not be 100% OEM, but it should do the job for you.

Check for a wire with 12v only when the key is in the "ON" position.