Help! Cuda won't crank

[matt63]

After spending all winter building my 408 stroker I thought I would finally get it started this weekend.  That didn't happen.  I bought the car in boxes and have never had it running.  I'm hoping someone can agree/disagree with my troubleshooting here.  The car is a '73 Cuda 340 4 speed.

Right now the engine won't crank.  It will if I jumper the starter relay (which is new).
There is no power to the yellow ignition wire on the starter relay (in run or start position)
I then noticed that the engine and forward lamp harnesses do not match the dash harness.  The yellow ignition wire and a few others are mismatched.  I think that the harnesses under the hood are '74 not '73 as there is a plug near the starter relay which I believe is for the seat belt interlock which is supposed to be for '74 only???
I remapped the wires in the bulkhead plugs so they match up although I don't know if I will ever have lights again now.
The engine still won't crank.
I checked resistance on the yellow wire at the firewall and the column and at the ignition switch and nothing changes in any key position.
I'm guessing that the ignition switch is bad.  I am hoping I can get one in town tomorrow.

Also, where is the neutral safety switch?  The tranny only has a 2 prong switch which I assume is for the reverse lights.  There isn't a switch on the clutch pedal or shifter.

[JS27N0B]

You need to have battery voltage on the large gauge wire to the ignition switch. Yellow should be powered up when in crank position only, blue should be powered when in the run position.
4spd cars had a clutch pedal safety switch that would only supplu ground to the starter relay terminal when clutch pedal was depressed. You can ground this wire permanently if you do not have a clutch pedal switch.

From what I get out of your trouble shooting it is very likely a bad ignition switch.

[Bullitt-]

make sure the terminals on the relay are tight.
link to diagram http://mymopar.com/wiringdiagrams.htm

[Bullitt-]

Checking the '73 service manual It appears that the START wire from the column is S2-12Y (yellow?) goes to bulkhead #9 into engine compartment remains S2-12Y which goes to the starter relay terminal "I" which in the picture is thingyed 45deg. I do not see anything about a lockout for manual trans. I had a '73 Duster 340 3spd & I know it cranked in gear. The only reference is to a backup light switch which I believe is on the shifter but not at all sure.  The other wire brown w/yellow stripe goes thru the seat belt relay & buzzer. I disconnected my seatbelts harnesses years ago & never had an issue on my automatic. New find somehow on manual trans. the seat belt relay is connected "to parking brake lamp switch" could this be part of an interlock? 

Based on what JS27NOB says it appears you could jump the brown/yellow to ground & eliminate any possibilty that an interlock is the problem

 Does the rest of your electrical system seem to function? radio heater wipers to indicate power is getting into the system? If not check the fuseable link at the starter relay, a blue wire that comes off the big nut, then plugs into a red wire.

[matt63]

The rest of the system seems to work ok although I haven't tested for power in the run circuit yet!  I'm a little concerned as this seatbelt interlock plug has 2 yellow, a blue and brown wire in it.  The solid yellow wire is for the starter relay ignition wire.  The blue and brown wires run to the ballast resistor.

Once I get the new ignition switch in I'll find out if the neutral safety switch works or not.  The 73 wiring diagram I have shows a clutch neutral start switch that runs separately through a grommet in the firewall.  I have a wire like this but it goes to the reverse indicator light.

[Bullitt-]

Is it possible that the interior wiring is '74? I don't want to start you down a wrong path but I will share with you We had a '74 Monoco that had an interlock as part of the seatbelts that would not let the car start. I disconnected wiring under the drivers seat & everything worked fine afterward. 

[Super Blue 72]

Is it possible that the interior wiring is '74? I don't want to start you down a wrong path but I will share with you We had a '74 Monoco that had an interlock as part of the seatbelts that would not let the car start. I disconnected wiring under the drivers seat & everything worked fine afterward. 

Good thinking.  Worth a shot. 

When I was about 6-7 years old I was in our '74 Chrysler Town and Country wagon and reconnected a couple little plugs under the driver's seat.

My dad couldn't get the car started for hours!  Boy was he pissed! 

[matt63]

Is it possible that the interior wiring is '74? I don't want to start you down a wrong path but I will share with you We had a '74 Monoco that had an interlock as part of the seatbelts that would not let the car start. I disconnected wiring under the drivers seat & everything worked fine afterward. 

I think that the engine wiring is '74 because it has the interlock plug near the starter relay.  I am pretty sure that the dash wiring is '73 as it doesn't match up.  Also, I have a spare dash harness but I think it is '74 as it matches the engine harness.  I'm guessing the PO gathered some spares up not knowing that they wouldn't fit.  The tranny, shifter and bellhousing didn't fit either!

[Bullitt-]

Have you tried just gounding the terminal on the relay for the brown/yellow stripe yet?

[matt63]

Have you tried just gounding the terminal on the relay for the brown/yellow stripe yet?

Yep.  There is no power to the yellow ignition wire. That is the problem.  I'll have a new ignition switch tomorrow.

[ShelbyDogg]

Matt, the wire going throughthe firewall is for the reverse light on the dash, by the ashtray. The clutch safety switch wire comes through the firewall on the inside, between the fender and brake booster. We'll work on that later.  But for now;
Start at the ignition switch yellow wire. when the key is in the crank position, does your test light come on?   

Rob

[matt63]

The new ignition switch will solve that problem.  The neutral safety wire goes through the firewall at the bulkhead connector with the rest of the wires although I haven't traced it to find out where it goes yet.

[Bullitt-]

Way to go MATT

[ShelbyDogg]

You don't have a neutral safety switch on a manual car.

Good luck with that...

See ya!

[matt63]

You don't have a neutral safety switch on a manual car.

Good luck with that...

See ya!

Yes, the manual calls it a "manual transmission clutch start switch" or something like that.  I don't see any switch on the clutch pedal linkage.

Anyway, the ignition switch is installed and the engine cranks now! (with the starter relay ground connector grounded)