I've been having the famous intermittent no-crank, no-click issue and have been trying to track down the culprit with circuit testing. I have not had a chance to trace the harness wires to investigate exactly what goes where yet. It had appeared that someone installed a four wire relay at the firewall that energized the starter coil, but the red wire was not connected and it's been this way for the four years I've had the car. Two green and one black are connected. The red wire tests 12v hot at all times which I know is not correct. I'm thinking this might have been used as a quick "jump" method since it's always hot and connecting it to the pin would apparently send power to the starter coil. Good thing I didn't try to connect it when I saw it was disconnected.

So I've now deduced that the relay is not active in any circuit. I can take it out of the system and the car starts just fine. That leads me to ask, is it possible to go directly to the starter coil with the 12v ignition wire and bypass a relay altogether? If the ignition wire is only hot when cranked, wouldn't that achieve the same result as with the relay? Finally, to what detriment might there be not using the relay at all.

Sorry if these are really dumb questions, but this is an area I'm just now learning about.

The car is a '65 L-76 non-AC.

Where would the original start circuit relay be found if it was in use?

Thanks very much,
Rick

 

The solenoid on GM and Ford starters IS a relay... Many don't realize that - it takes a small signal from the ignition circuit and uses it to engage the hi-amperage circuit to engage the starter... So - you can short across the solenoid yourself to engage the starter....

CAREFULLY, with car in neutral, parking brake on and wheels chocked...and ignition key in the "ON" position.


Or you can use a remote starter switch which is useful for many other reasons and avoid the drama and sparks:

 

Well that's a great answer and clears things up a bunch, thank you! Now I have to trace the errant relay that appears to not be in use and figure out what is was supposed to do. It still looks like it might have been used as a bubba method to short the starter solenoid from under the hood instead of having to get under the car.

 

Who knows - it could have been wired up as a "kill switch" (to prevent starting by thieves) or a burglar alarm or whatever...
You may never figure it out. If the "trigger wire" is still connected and you can trace it to a factory harness or separate aftermarket switch it would help.

 

I traced the non-working relay back to this "Delco Remy" part, but don't know what it is...maybe the horn relay?

The black/pink wire is only energized when the ignition is turned, but the power to this relay was not connected.

So my question is: What is this part and if it's not getting 12v on ignition, what is apparently not working?

Thanks again.

 

Mmm....what Delco-Remy part ? If its a silver, metal box on the radiator core support with red wires hanging off of it then its the horn relay. The terminals on that part are a major power buss in the car and where aftermarket accessories should receive power.

Some cheaper burglar alarm setups would honk the horn if the car was started illegitimately.
I think I'd just remove that relay and associated wiring and if everything works - just move on.

 

It's actually the black box to the right of the silver metal one. Maybe that is an old alarm?

 

Need a picture. The black voltage regulator is in that same area.

 

That black box is voltage regulator. It is used to regulate the voltage coming out of the alt to the battery. The only way it could not be used if a previous owner replaced the original alt. with a later model internally regulated alt. Jerry

 

Yup.

 

You need to get a wiring diagram. There is no oem relay, just the solenoid as Frankie noted. There are two wires that matter to you. The first is the ignition wire from the ignition switch that comes through the firewall near the windshield wiper motor and goes to the ballast resistor. This turns on the coil. The second is the start signal from the ignition switch to the S terminal on the starter. Locate these wires, visually inspect they are connected properly and then test voltages. You will find the problem. Good luck!

 

OK, thanks.

The alternator was replaced not too long ago. Is there any reason, whether in use or not, the voltage regulator would need ignition 12v? Still can't figure out the function of the mystery relay.

On a good note, I did find that I'm only getting about 9v at the starter solenoid, so it looks like I'm getting closer to solving my hot no-start, no-click issue. Now I have to trace it back to either wiring, firewall connector or ignition switch.

 

Yes and the universe works in a mysterious way...I found a post just today of someone offering wiring diagrams so I've requested mine.

I do have a service manual but I think the relay connected to the starter threw me off...couldn't find that!

 

Hey Frank, one more question if I could:

I found the voltage drop to be in the ignition switch. Supply at the switch is 12.6v battery power and the wire out to the starter solenoid is 9.4v. Found the culprit, but don't know if it's the plastic harness or the switch casing. I put my test probe right into the back of the harness for the reading. Seems like it has to be the ignition switch casing that's bad. Would you agree with that? Doesn't seem to be much to the casing, but I guess it's the contacts that are bad. Is this something that can be cleaned up and returned to service?
Thanks.

 

If your measurements are accurate then yes that's the problem. I would do one more check to eliminate variables....take the connector off the ignition switch and measure the resistance (ohms) between the two contacts you cited above.....if its not real close to zero then that's your problem. I've taken apart headlight and wiper dash switches but never an ignition switch, but if its bad anyway - there is no downside to easing it apart to see if something can be fixed. Might want to be sure you can line up a replacement first though. But, you could just remove it and get some DeOxIt electronics spray and hose the living snot out of it, like dousing the keyhole with the lock cylinder removed and spraying through any cracks or holes in the back - a long shot but it could work. if the problem is corrosion.

Some switches, like for 65 (like yours) / 63 are rare and the repros are dicey.

And now I wonder if some prior owner had the same problem and just hooked up that extra wiring to get the car running ?!?

 

Thanks, I'll definitely do the ohm test later today. Another great idea I didn't think to do. I have another month of driving here in NJ before the weather gets too bad so I'll tack this onto my already long winter list of projects. I looked up the part on various sites and yes, it's pricey. It certainly will be nice to put the "wonder if it'll start if I stop for a sandwich" behind me though. And yes, I can completely see the mystery relay was a quick jump method similar to a remote ignition switch the previous owner had installed. Thanks again!