88_N/A_GXL

iTrader: (3)

So, I've been trying to wire in a new 5 pin relay to the stock location of the starter cut relay to switch power from the starter to a secondary alarm siren, but I can't seem to get the relay to engage.

I've used both a test light and a multimeter to attempt to diagnose if it's the relay or the wiring and with the test light connected to the negative terminal of the battery I get nothing on any pin on either the stock relay or the 5 pin replacement and with the multimeter on the positive terminal I get ~12v at every pin but I know both work as I have tried them both directly to the battery a few times to check.

Originally when I bought the car there was an aftermarket alarm wired in but a hot summer and black tape decided that I didn't like it falling on my left foot anymore. So, it has since been removed and repaired as far as I can tell, mostly wire taps so nothing too mangled up. This has been a while back and I'm not sure if anything above the clutch pedal runs to where I may or may not need to re-evaluate, so just throw suggestions out and I'd gladly go check.

Hopefully somebody may have a flowchart or system diagram of an S4 theft system, if such a thing does exist, though through all my searching I've yet to find one.

Thanks for any help in advance.

DC5Daniel

iTrader: (10)

I don't quite understand how you don't know why the relay is not activating, unless you don't know how to use a multimeter or how a relay works (I'm not trying to be a dick, honest). The coil of the relay simply needs to see ground on 85 and +12V on 86, or vis versa the polarity is indifferent. You will hear and feel a noticeable "click", this is the simplest way to determine if it's activating. If you have any multimeter experience it should be very easy for you to verify that you have a good ground signal and 12V feed. Please do a bench check by simply applying 12V and ground to the coil and verify the relay is not faulty, which is always a possibility.

88_N/A_GXL

iTrader: (3)

Okay, so I finally had my aha! moments yesterday and today. It turns out that the stock circuit for the starter cut relay does not engage anything unless the key was turned, as the positive side of the control on the relay is switched power. Which made it a tad hard to deduce at first, I'm not too great at circuit diagrams but am getting better. I figured all this out yesterday.

Today it turns out, the way I had it originally wired it would only click over the 5 pin relay during cranking, which I only just realized today, which only fired off the siren as you crank. Which is a no-go for what I wanted. So, I reexamined my circuits and realized that it was a rather simple fix, put another relay in front of the power side of the control circuit on the starter cut relay. Now, I have fused power into both 30 and jumped to 85, the siren on the NO (normally open) connector, a wire from 86 on the first relay to 85 on the second relay, the stock B/G wire on 30, stock B/W on the NC (normally closed) connector, and the stock security LG/Y wire on 86. I've left out the smaller stock B/G wire in the circuit as I have the first relay up front, right behind my driver side headlight, and I did not want to extend that wire.

I've included a diagram for anybody else who wants something similar, like alarm activated power to whatever. Note on relays: 85/86 can be switched without worrying, and be sure to determine what contact, 87/87a, is normally open or normally closed to decide what you want to do. I don't remember which are what on mine but, to keep the starter cut and have switched power, one has to be on 87 and the other on 87a. I'm using just standard ford relays I've pulled from under many hoods in the junkyards.