Starter relay confusion

[2ndwind]

O.K, I have the intermittent starting issue and would like to put in a relay.
I obtained a 30A 12V relay, red 10 Ga and 12 Ga stranded wire. I am unsure which wires are which on my '82 5spd.
looking at the solenoid from the front, it has 2 heavy green wires and 1 brown wire going to the terminal. There is also a red wire that goes to a push-on terminal it looks like this from the front of the car:

and this from above:

The alternator has no red wires coming out of it only a heavy black, very heavy green and light black from a push-on terminal:

In the alternator picture you can see the connectors running below on the red and brown wires which I understand ought to be soldered and shrink-tubed. Is one of these the wire to run to the relay or not?


The clean wiring diagrams of Brad Artigue's and the drawing of the Ford relay installation don't help me with what I am looking at.

Thanks in advance.

[htchevyii]

I'm not really clear on what you're trying to accomplish here? The solenoid acts as a relay, the wire from the switch just activates the solenoid. I do not think the wire from the switch has much amperage run thru it. The Ford solenoid would be on the main battery cable but it much bigger than 30 amps. I don't see much of a reason to do this, unless you are fighting voltage drop or something, ( the Ford solenoid on the batt cable, that is).

[2ndwind]

Thanks Trey,
I understood from elsewhere on the forums that there is too much amperage running through the ignition switch contacts to get reliable starting over time, thus people are putting in relays to reduce the excess current required. Am I confused on this?

Here's the thread:
http://www.fiatspider.com/f08/viewtopic ... ay#p101095

[spider2081]

I believe the red wire with the push terminal at the starter solenoid and the red wire with the single connection in your later photos is the same wire. If you pull apart the red wire connection below the alternator one end should have 12 Volts on it when the ignition switch is in the start position. The other side of the connection is the wire with the push terminal on the starter solenoid.
I Connect a 20 amp inline fuse to the alternator output and connect it to the movable or common contact on a relay. the normally open contact that mates with that common connects to the end of the red wire that goes to the starter solenoid. One side of the relay coil connects to the red wire from the ignition switch that is 12 volts in start only. The other side of the relay coil connects to ground.

The alternator output has battery voltage on it all the time so be sure to disconnect the cars battery before you try and take the nut off that terminal.

Hope this is some help

[jimincalif]

The red wire on the push on terminal is coming from the ignition switch. This is the wire you want to connect to one terminal on the low current side of the relay. The other terminal on the low current side connects to ground. You should be able to extract the red wire from the harness and route it to a suitable location to mount the relay without having to cut it. While you are at it, open the inline connector and clean both sides of it. Spread the male side pin a bit and put it back together with dielectric grease and make sure it is good and tight.

You then want to run the 12g wire from either the large terminal on the starter or the alternator power terminal, to one terminal on the high current side of the new relay. Then run another 12g wire from the other high current side of the relay to the push-on terminal on the starter solenoid.

Now, when the actuate the key, it closes the relay, which relays the power to the starter solenoid.

I chose to make my connection from the large starter terminal to the relay as that is where the battery cable terminates. This eliminates the smaller wire and its two connectors between the starter and the alternator power terminal from the starting circuit. Each connection is a weak link.

[azruss]

nice exercise you are going thru. not sure it will solve your problem. A common source of intermintant starting issues is a bad solenoid. common for the connecting plate to get dirty and make a bad connection. also the solenoid shaft itself gets worn and makes a weak connection as well.

[courtenay]

Not sure what is actually happening with your starter problems, but you might want to look at this thread...
http://www.fiatspider.com/f08/viewtopic ... a&start=15

[2ndwind]

Thanks everybody. The starter (and solenoid) are only 1.5 yrs and 4,000 miles old, car is garage kept. I appreciate everyone's taking the time to help out. Courtenay, I have reviewed that thread and am planning on eliminating the extra connectors both below the alternator and behind the ignition switch too. Will solder and shrink tube them. Thanks again everybody.

[SpiderJim]

Installing the relay makes a huge difference. I know many agree and also disagree. However, when fairly high current is switched via the ignition switch that is not the highest quality to begin with. Stuff breaks down, heats up and generally begins to buildup impedance that reduces current flow and hence a series of false starts. I had this plague me all last year even after a new ignition switch and all related connectors being cleaned. I added the generic ford starter relay via the drawing below and have not had one false start todate. Most cars I have ever owned both collector and new use relays so someone is designing correctly!. I also added the two high/low beam relays for headlamps.

[surfingfreeman]

Nice schematic Jim!

[2ndwind]

Relay installed! The red wire running along the inner fender below the alternator (in my picture) is/was indeed the wire from the switch to the solenoid push-on connector. I wired the relay just as you have it Jim. I soldered all the ends onto the wires and put shrink tube over each. Also I soldered together the brown wire shown below the alternator (and shrink-tubed it). Next is eliminating the connector just behind the starter switch.

Thanks again everybody.

[mighty7]

I just bought a wire tracing tone generator at my local hardware store. Great for tracing wires and even finding mistakes in some of the wiring diagrams that I see out there and even purchased. Best $30 ever.

Clip the signal generator to one end of the wire your are tracing and then the pen like other end can follow along the wire bundles and a tone will be heard when you are near the wire with the generator. You can then isolate that wire within the correct bundle.

[blurple124]

FYI, the current draw on my solenoid alone was measured at 40 amps. I, too, am installing a relay to switch the solenoid, and a 30/40 should be okay since the use is intermittent, but beware that we are running awfully close to the limits of those relays. Let's hope they have a decent safety factor on that rating.

[majicwrench]

40 amps to energize the soleniod?? I'm gonna doubt that, but till I can grab a starter and test it, just a guess that a soleniod would not take near that much. Heading to the shed...
' Keith

[seabeelt]

I have to agree with azruss on this. The solenoid is a relay of sorts. The red wire energizes the solenoid (magnetic coil portion of a relay) and drives the switch arm over to the starter. The switch arm completes the circuit between the battery cable and the starter motor. The big current draw is on the battery cable to the motor itself, hence the size of the wire being so big. That's not to say that the solenoid doesn't have a hefty wire compared to most wires in the car, it does, but it is not the major current draw. Adding an additional relay will in effect double relay the same circuit. I'm not seeing much gain if any from this effort. Just my 2 cents

I also doubt the 40 amps, based upon the red wire size. The largest fuse in the fuse box is (or should be) 25 amps for that size wire going to and from the fuse box.

Second 2 cents, ok a nickle
R/