Starter relay question

My 1970 Dart didn't want to start but it did when I jumped the starter relay. So I got a new relay and I have the same issue. I was checking wires with my multi-meter and found that the black ground wire on the relay is carrying nearly 12 volts. I ran a temporary ground from the lug on the relay and it started right up.

Anyone have any idea where to look to see how the ground wire is getting voltage? Could it be a problem in the ignition switch?

UPDATE: I just discovered the lights in my gauge cluster aren't working. Could a short in the dash pass voltage to the starter relay ground??

You jumped the "G" terminal to ground & it started? If so see why the downstream end of the black wire ain't being grounded when you put it park/neutral.

Are you suggesting it is the neutral safety switch? I can check that, but would a problem with the neutral safety switch put voltage into the wire? Does the neutral safety switch carry voltage?

UPDATE: I just discovered the lights in my gauge cluster aren't working. Could a short in the dash pass voltage to the starter relay ground??

The neutral switch is just a switched hard ground. The wire going to it will have 12 Volts waiting for that ground to short it and the relay will close..

That black wire at the starter relay when removed should show a dead short looking at the neutral switch. If you do not see that dead short, the wire or the switch is defective.

Is your neutral switch in the transmission or on the shifter inside the C0ckpit?

Your Dash light issues are something else most likely.

In an electrical circuit like the relay, you have a coil wire attached between the starter switch power source 12V terminal on the relay and the ground terminal waiting to be grounded either thru the neutral switch or manual clutch switch. When no ground or path back to the source battery exist there is no current flow, but the voltage applied at the terminal can be seen all along the point of connections. (in this case right to the neutral switch) So yes chances are your neutral switch is the issue. Especially since you remove ground wire and had continuity back to the terminal. Your added ground wire jumped all the safety switches out of the circuit, so when the ignition key produced the 12V, the car started.

Illustration to go with Sniper's explanation.

When the key switch is in Start position and the relay's electromagnetic coil is grounded, the circuit is completed.
Inside the starter is a larger more powerful electromagnet - the solenoid. It works the same way but draws power direct from the battery through the heavy (4 or 6 ga) cable.

Indirect answer to Dash lights.
Normally when the engine is turning the alternator, the alternator supplies power around 14 Volts.
When that's not happening, the battery supplies power around 12+ Volts.
Voltage is like pressure in a water or piped air system.
Amperage is a measurement of flow like gallons per minute for a liquid, or cfm for air.

This is important when trying to figure out what is happening.
The ammeter shows current flowing from the battery. If any circuit is completed, the needle should move. It will move tiny amount for dash light, more for dome light and brake lights, and so forth,
Voltage (pressure) is always present if a wire is connected to the battery positive. It doesn't matter if current is flowing.
So two different tools.

The dash lights get their power through the fusebox withough going through the key switch. That circuit is always hot. It is controlled through the headlight switch.,
The dome light is also always hot, as is the dome light itself. It's controlled by any switch on the return line, including a portion of the headlight switch. Any one of those switches completing the circuit to ground.
All wires connected to the battery positive, including the alternator output wire are always hot. If any of them are accidently grounded the battery will discharge big time! So be careful!

take the black wire off of the G terminal on the relay. connect the G male terminal to a good ground with a jumper wire. trans in park or neutral. turn the key & see if it cranks. If no go the NSS at the trans or shifter ain't grounding it in park/neutral like it should which you are duplicating that with the jumper. the black wire from relay down to the NSS could have a break (open) in the wire but not likely.

Dash lights might be the headlight switch section. Try turning the brightness up and down to se if the rheostat is good.

Thanks to everyone for all the help and suggestions so far. I still have the same issues but I have some more information. First, it is definitely NOT the neutral safety switch. I'm sure of this because I don't have one. I converted the car to a Tremec TKO600 and we decided to forego the safety switch on the transmission and just use the one in my brain.

I have some auxiliary gauges that are wired into the lighting circuit for the dash cluster gauges. The auxiliary gauges light up and dim when I turn the headlight switch, but the OEM ones don't.

Any ideas out there?

That would have been good information to have earlier.



Is this still the case?

No NSS means you still have to ground the G (ground) terminal to make the relay work. A simple loop to a known good ground will work. The I terminal should be the start wire from the switch (yellow) and get hot in the start position.

Are these new starter relays maybe made in china, if so wack it and try to start it.

Manual transmission starter relays were available in 2 styles. Early, where the ground lug in question was soldered directly to the case. Thus that circuit was always grounded. Late, where the circuit in question went to a clutch switch. The switch grounded when the clutch was depressed. So you had to push the clutch to crank. Grounding that circuit is all you need if you don't desire the clutch option. The light issue is not related.
Doug

Funny how answers are all over the place. This is a 1970 car. So it should have a safety switch. Having said this, the owner has not really provided good info. Is this an Auto car swapped to manual or a manual car swapped to new TKO manual?

A manual transmission does not have a safety switch. It has a backup light. The safety switch was on the clutch petal as explained. Did you remove that too?

It really is simple, you add a ground wire and it works. Since you want to use brain instead of safety switch, keep the ground you attached in place. Your done. I already explained why in an electrical circuit you see voltage even if the circuit is not drawing current.

You next problem is dash lights if it still exist.

I know Matt's car a bit, he's had it for maybe 30 years.
It was converted from AT to the Tremec several years back and has been driven a fair amount since.
But IIRC it does sit for periods of time in his home garage.
That tells me something has changed or deteriorated.
I've had a starter relay with a loose terminal that would occasionally no-start; wiggle the connection, and it would work.
Matt, look at the other end/connection of whatever grounded the relay before, including the wire itself.
Could even be a faulty replacement relay, ground shouldn't be carrying 12V, right ?

Dash lights: so the dimmer rheostat works the A/M gauge lighting OK, but not the cluster lamps ?
I'd look at whatever the different routing for those two is, including the big connector at the back of the cluster circuit board.

Any circuit that is looking for a ground that has an open, like you remove the ground source, will have line voltage potential. This is how 95% of things in a car/truck work. You open the car door and the switch at the A pillar goes to ground and the dome light goes on. But pull the grounding door switch out and measure the voltage at the Yellow wire and you will find 12+ Volts DC.

Actually, I've had it for 23 years, but otherwise your remember correctly. It was a column shift automatic and when I installed the Tremec I used a steering column out of a 71 or 72 floor shift Duster. I agree that I think something has deteriorated. I've never had an starting issues until after this winter's hibernation, and no dash light issues either. And just to be clear, the ground wire shows battery voltage whether it is connected to the relay or hanging loose. I guess it could be a coincidence that these 2 issues developed simultaneously, but it seems weird. I guess I need to start wiggling wires and checking grounds.

Look for rodent damage. A ground wire hanging loose from the relay should not have 12v on it.

^^^ agreed, the ground wire out from the G terminal should only be hot in ign2 "cranking" ign switch position

What does hanging loose mean? Loose from ground point or loose from relay. Yes big assumption that when measuring voltage he had ignition on. Not off.

If he has ground wire on frame of car and it measures 12V when hanging loose, he does have other bigger issues and I assume that would also mean the ground wire from battery is no longer attached to frame or battery since that would be a direct short across the battery and boom. But since he hung a separate ground wire to the relay and the car started, I don't think that is the case. Now, certainly it may be a works sometimes not other times relay, but..... he swapped in one.

So I guess we could ask, where do you ground your starter relay too (originally), since the safety switch was removed?

There was not enough information in the first few posts and then the information after is kind of scattered.

How I would do this, IF I think this is going, is to isolate that wire he has voltage on. See where its getting its 12 volts and remove it.

The Neutral switch lug on the Starter Relay, I would just make a 5 inch black wire with a female spade on one end and an eyelet connector on the other. Put the spade on the neutral lug and the eyelet under the bolt holding the Starter Relay down, BOB's YOUR UNCLE!

Loose from the relay. If it's not plugged into the relay and it's hot, it's not a ground.

Ground it anywhere. Sheet metal close to the relay will be easiest.

If it was working and now it's not, something changed. Lights not working, ground wire is now hot. I'd be looking at harnesses for rodent damage. Any fuses blown?

I'm sold on the idea of running a new ground. (I actually got the same advice from Richard Ehrenberg). Now I need to figure out why the all the gauge lights are out. I checked the fuse and it's good. And when I pull out the headlamp switch I get 12 volts at the fuse. So, unless all the bulbs blew out somehow, I guess it has to be a ground issue.

So can anyone tell me how the gauge cluster lights ground? I've tried looking at the wiring diagram but it isn't clear to me.

Grounds through the screws that hold it to the dash

^^^^This!

Did you mess back behind the dash, even a little? The dash printed circuit board has (Off the top of my head) 8 pins that are crimped on the board. The connector goes on those pins. They have been known to get loose and snap off. So if you got your mitts back there you could have goggled one loose. They can be reinserted and swedged back on but it is fiddly work.

You are only 480 miles southeast of me, I'll be right over.... Really if you were within 100 miles I'd head over to look. But 8 hours is a bit much.

Nope, I haven't been up behind the dash for anything in years.

The dash lights are dimmable no? Car sitting can cause electrical contact issues (mild oxidation). Cycle dimmer switch and light switch. Add a ground wire to the panel frame. I did that as backup on my dash.

I don't mean to hijack this thread but I am experiencing pretty much the exact same problem right now as MadMatt with coincidentally, my 70 Dart. When I got the car out of storage it started fine. Put it back in my garage where it sat for a week or so. Went to start it a couple of days ago and it cranked over but I prematurely let off the key before it actually started. So I turned the key again and it won't crank over and still doesn't each time I try. I have checked pretty much everything I can think of. There is power at the yellow connector on the starter relay with the key turned to start and if I jump the relay, it will crank and start. I have checked and cleaned all of the connections on the starter relay including where it bolts to the fender. I have checked and cleaned all of the bulkhead connectors as well as the neutral safety switch connections and I have tried 2 new starter relays. Still won't crank with the key.

Did you check that the neutral safety switch is giving you a ground when in neutral?

Turns out we were putting car back together from a resto, and it would not start via key. Turns out relay was bad. So I took the bad one a part. Turns out it was pristine inside and the coil was not bad. What I found is that the 2 terminals used to activate the coil are assembled in 3 pieces. Brass terminal, brass rivet, and inside terminal that the coil is soldered too. When I checked coil from inside it was fine at 25ohms. When I checked coil from terminals as the ignition system would use it, it read open.

Turns out on both terminals the inner contact had no continuity to the outside spade, and on one terminal the rivet did not even have continuity to the terminal. So they must have had a heavy varnish/coating that insulated the connection. Really a bad way to build this with 3 independent connections. Having the spade terminal go fully through to the coil wire and rivet would have been much better. No joint and the rivet is only responsible for mechanical binding, not actually continuity.

I clean the rivet and soldered the inside terminal to the rivet head, and on the terminal that had bad continuity to the rivet, I flowed flux on it and heated with solder iron to burn off any varnish, then flowed some solder under the rivet.

when you say jumping the relay if you are grounding the G terminal & it now cranks then what Dragon Slayer said, see why the NSS downstream ain't grounding the G terminal like it should

Elementary electronics, so basic & so simple yet it kicks so many peoples buts, understanding electronics can really be confusing,like when electronic Ign. came out in the early 70s what a game changer.