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Old 03-28-2015, 10:07 PM   #1
Gregski
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Truck Won't Start No Sounds No Noises Nothing

apologies for yet another truck won't start thread, hope you can walk me through troubleshooting this

1974 GMC 1500 1/2 ton V8 350 4 spd manual on the floor, brand new ProForm HEI dizzy installed months ago and working fine, not sure how old the starter is or the alternator

this is a daily driver (sort of) I drove it in to the garage couple days later it won't start

FYI I have a neutral / clutch pedal switch bypass on the purple wire under the dash that the previous owner put in and it's been there and working fine for years

PROBLEM - turn the key, the dummy BRAKE red light goes on the dash but the car makes absolutely no sound, no clicking no vrooming nothing, heater fan turns on and blows, wipers work, headlights work, horn does not but that's because it's broken

STEP 1 - Battery (well mine wise 3 years old and the wrong group size so I raplaced it with a brand new one, brought it home fully charged) truck still won't start with the new battery same issue

STEP 2 - Fuses, all look good

STEP 3 - ? Starter? I don't think I have power going to the purple wire that goes to the starter, I put a test light on it and had my son turn the key and the light does not turn on

How can I bypass the ignition switch in the steering column and just jump start the thing from the bulk head connector?
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Old 03-28-2015, 11:00 PM   #2
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Re: Truck Won't Start No Sounds No Noises Nothing

Hey Gregski
You're doing well with the troubleshooting so far. Here's what we know:
Ignition switch is still getting power and providing power to ignition hot devices.
Battery has at least some power.
No power on the purple wire is definitely a problem.

The purple wire provides power to the solenoid on the starter (but not the starting power itself). When the solenoid pulls in, it closes a much larger contact that actually gets the starter cranking.

So, there's a break in the purple wire between the ignition switch and the starter. There's a slim chance that the ignition switch starting contacts are faulty, but I wouldn't start there.

Now, if you just want to start the truck, put the switch in Run, then jumper a wire from the purple wire terminal on the starter to +12. You can do this with a screwdriver, but I don't like that method myself. Of course, make sure you aren't in gear, because there's no interlocks now!

As for fixing the real problem, use your probe light, and start at the wire at the ignition connector on the steering column. Keep probing along until you find where the wire is broken.
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Old 03-29-2015, 08:05 AM   #3
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Re: Truck Won't Start No Sounds No Noises Nothing

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Originally Posted by Gregski View Post
apologies for yet another truck won't start thread, hope you can walk me through troubleshooting this

1974 GMC 1500 1/2 ton V8 350 4 spd manual on the floor, brand new ProForm HEI dizzy installed months ago and working fine, not sure how old the starter is or the alternator

this is a daily driver (sort of) I drove it in to the garage couple days later it won't start

FYI I have a neutral / clutch pedal switch bypass on the purple wire under the dash that the previous owner put in and it's been there and working fine for years

PROBLEM - turn the key, the dummy BRAKE red light goes on the dash but the car makes absolutely no sound, no clicking no vrooming nothing, heater fan turns on and blows, wipers work, headlights work, horn does not but that's because it's broken

STEP 1 - Battery (well mine wise 3 years old and the wrong group size so I raplaced it with a brand new one, brought it home fully charged) truck still won't start with the new battery same issue

STEP 2 - Fuses, all look good

STEP 3 - ? Starter? I don't think I have power going to the purple wire that goes to the starter, I put a test light on it and had my son turn the key and the light does not turn on

How can I bypass the ignition switch in the steering column and just jump start the thing from the bulk head connector?
The P/N safety switch might have moved slightly. You might try to start it in neutral and if it doesn't start, then move the shifter around slightly in the neutral position with the key in the start position. If it starts, the switch needs to be adjusted.
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Old 03-29-2015, 08:28 AM   #4
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Re: Truck Won't Start No Sounds No Noises Nothing

Your problem is consistent with the last tooth on the sector gear in the steering column being broken. That last tooth is what lets the ignition cylinder move the ignition switch to the start position.

I bypassed mine after it broke the 3rd time. Used a push button switch to bypass the start switch on the ignition switch.
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Old 03-29-2015, 11:03 AM   #5
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Re: Truck Won't Start No Sounds No Noises Nothing

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The P/N safety switch might have moved slightly. You might try to start it in neutral and if it doesn't start, then move the shifter around slightly in the neutral position with the key in the start position. If it starts, the switch needs to be adjusted.
On a manual transmission? I did and that did not work.
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Old 03-29-2015, 11:19 AM   #6
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Re: Truck Won't Start No Sounds No Noises Nothing

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Your problem is consistent with the last tooth on the sector gear in the steering column being broken. That last tooth is what lets the ignition cylinder move the ignition switch to the start position.
Would this still be the case if my key moves fine into the start position? It's not like there is something preventing it to move there, it's just when there nothing happens.
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Old 03-29-2015, 11:26 AM   #7
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Re: Truck Won't Start No Sounds No Noises Nothing

Yup, mine did the same exact thing until that little toothy gear piece completely snapped in half.
I could get buzzers, lights, everything going but my starter. It started off as a slow break where I would have to wiggle the key and column to get it to start, as well as turn the key as far as it would go. Before it completely went I could turn the accesories on without the key.
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Old 03-29-2015, 11:29 AM   #8
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Re: Truck Won't Start No Sounds No Noises Nothing

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On a manual transmission? I did and that did not work.
Sorry missed that. You might check the starter switch. It is located on the column above the fire wall. When the key is turned, a rod from the gears DP mentioned, pushes the start switch. If I remember right, that switch is adjustable and it might have slid down the column. You should be able see the rod push when someone turns the key.
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Old 03-29-2015, 12:06 PM   #9
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Re: Truck Won't Start No Sounds No Noises Nothing

trying to simplify the troubleshooting process, so I made this diagram maybe it helps somebody out, it brushes aside all the extra wires and just says, here this is how power comes in to our trucks, no thrills about it, correct me if I am wrong, but it basically goes battery to starter to fuse box, so it relays through the starter for some reason, maybe that's how all cars work I don't know, I was surprised to find out and learn that myself
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Old 03-29-2015, 12:17 PM   #10
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Re: Truck Won't Start No Sounds No Noises Nothing

Use your test light to check for power at the previously mentioned jumper wire at the clutch switch. In the start position you should have power on both sides of the jumper.
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Old 03-29-2015, 02:30 PM   #11
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Re: Truck Won't Start No Sounds No Noises Nothing

went out to O'Reillys and for $20 bucks picked up this BOSCH remote starter, the kid at the counter goes what year is your vehicle, make, model... you know the drill, I told him the part number and Game Over it was hanging on the wall behind him but too low for me to see over the counter

always wanted one of these, but it is a bear to put on since the starter is tucked away under the car, we are not dealing with the solenoid on the fender like god intended here with nice long studs sticking out,

enuff ranting, did the truck start with this bypass, YES, yes it did, fired right up

ok, we are not out of the woods just yet, but wanted to give you all an update where I am at and thank you all for your advice, now the troubleshooting begins
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Old 03-29-2015, 08:32 PM   #12
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Re: Truck Won't Start No Sounds No Noises Nothing

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You might check the starter switch. It is located on the column above the fire wall. When the key is turned, a rod from the gears DP mentioned, pushes the start switch. If I remember right, that switch is adjustable and it might have slid down the column. You should be able see the rod push when someone turns the key.
OK, I think I found it, had to drop the steering column to finally see it, this vertical rod must be what you are talkging about. It looks good as does the ignition switch itself, I think I even pushed the black slider on the switch with a flat screw driver and the truck tried to start, and that was music to my ears...
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Old 03-29-2015, 08:37 PM   #13
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Re: Truck Won't Start No Sounds No Noises Nothing

So I guess its confirmed it to be that pewter ignition slider inside the steering column?

Thay sucker is a MONSTER to get to. Gotta pull the wheel, locking plate, turn signal switch and arm, remove three screws and remove the column cover and the peice will be on the left hand side covered with a dust shield plate.
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Old 03-29-2015, 08:43 PM   #14
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Re: Truck Won't Start No Sounds No Noises Nothing

after a bit of cleaning and reassembly of the ignition switch and the push rod I think I found the problem

I went to turn the key again and the rod would not move up and down, I thought what the heck

there may be even more crud inside the column to get out

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Old 03-29-2015, 11:17 PM   #15
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Re: Truck Won't Start No Sounds No Noises Nothing

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So I guess its confirmed it to be that pewter ignition slider inside the steering column?

Thay sucker is a MONSTER to get to. Gotta pull the wheel, locking plate, turn signal switch and arm, remove three screws and remove the column cover and the peice will be on the left hand side covered with a dust shield plate.
AMEN to that, plus you need a nine foot philips screw driver to get the housing separated at the end to get to the part you are after
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Old 03-29-2015, 11:19 PM   #16
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Re: Truck Won't Start No Sounds No Noises Nothing

ok, well lets go on a journey of a thousand pictures
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Old 03-29-2015, 11:21 PM   #17
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Re: Truck Won't Start No Sounds No Noises Nothing

still going...
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Old 03-29-2015, 11:23 PM   #18
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Re: Truck Won't Start No Sounds No Noises Nothing

ok not sure if this alumininum (or is it?) piece at the end of the push rod is broken or if it just looks like that
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Old 03-29-2015, 11:54 PM   #19
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Re: Truck Won't Start No Sounds No Noises Nothing

Just reading over this.. I know you simplied your wiring diagram up top but your starter should have 2 wires plus the heavy guage wire for the battery on your starter.

The 2 wires will lead to the junction block on the firewall and alternator and the 3rd goes to the battery. From that there should be a purple wire which feeds from the terminal at the 3 position closest to the block which then goes to the bulkhead connector and into the igition switch.

Its the purple wire which allows the truck to energize the starter to properly start.
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Old 03-30-2015, 10:43 AM   #20
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Re: Truck Won't Start No Sounds No Noises Nothing

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OK, I think I found it, had to drop the steering column to finally see it, this vertical rod must be what you are talkging about. It looks good as does the ignition switch itself, I think I even pushed the black slider on the switch with a flat screw driver and the truck tried to start, and that was music to my ears...
That's it. I was hoping you could see it from under the the dash while someone turned the key to see if the rod was moving or not. I've had that switch slide down the column to where the rod could not depress it enough and the switch go bad as well. Glad you found the problem, looks like you have your hands full.
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Old 03-30-2015, 11:42 AM   #21
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Re: Truck Won't Start No Sounds No Noises Nothing

Well you got farther than I did that's for sure! I got the cover off before I finally gave up and had it towed.
Mine looked like a tuning fork, yours obviously is not the same one as mine.

BTW, diggin the fact your still rocking the original radio!
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Old 03-30-2015, 02:16 PM   #22
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Re: Truck Won't Start No Sounds No Noises Nothing

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Originally Posted by enaberif View Post
Just reading over this.. I know you simplied your wiring diagram up top but your starter should have 2 wires plus the heavy guage wire for the battery on your starter.

The 2 wires will lead to the junction block on the firewall and alternator and the 3rd goes to the battery. From that there should be a purple wire which feeds from the terminal at the 3 position closest to the block which then goes to the bulkhead connector and into the igition switch.

Its the purple wire which allows the truck to energize the starter to properly start.
You are correct, but my diagram is not to show how to wire a starter or how to wire an alternator, it is to show how to get power to the truck. So lets say you wanted to troubleshoot your horn, my diagram shows you how the positive electricity flows to the bulk head, starts at the battery then through the starter, then to the block mounted on the firewall.
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Old 03-30-2015, 02:16 PM   #23
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Re: Truck Won't Start No Sounds No Noises Nothing

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BTW, diggin the fact your still rocking the original radio!
Yeah, LOL, but it don't work! maybe time to start another thread for that, hee hee
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Old 03-30-2015, 04:45 PM   #24
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Re: Truck Won't Start No Sounds No Noises Nothing

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Yeah, LOL, but it don't work! maybe time to start another thread for that, hee hee
I grabbed a working AM/FM Cassette Stereo Delco unit off Ebay for $99. The standalone AM/FM Stereo units can be had for around $50-75
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Old 03-30-2015, 08:14 PM   #25
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Re: Truck Won't Start No Sounds No Noises Nothing

right then, so after finding a long philips screw driver I pressed on, and managed to separate the black round steering shaft / column housing like so in order to finally extract the rest of the key cylinder and the damaged plastic spector gear (one tooth missing)
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