Husker6.5
135' diagonal 16:9HD, 25KW sound!
When the ignition switch fails, it fails 'Open' so that you don't crank (no voltage to starter solenoid wire)
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No crank with whining noise
- Thread starter Landon730
- Start date
Screw "View attachment" the site does to me above, here it is:
Patience young Padawan!
Trons take time and is a black art even by those who know what they are doing. So quit giving up and thinking about parting it out. Let's look at the diagram above and Connect The Dots!
In the upper right corner it covers the ignition switch. Below "Starter motor" it has the crank fuse and says "HOT IN START". So unless you are holding the ignition switch in "start" it's going to normally be stone cold dead. All it does is power a fuel pump relay BFD as far as lighting off the starter. As above it could indicate no power to switch from burnt fusible link or bad switch. Regardless Ignition power is coming from the red fusible link to the ignition switch, through the gear shift switch and then to a purple wire direct to the starter solonoid. Again in the crank position. The fun is tracking down what has and does not have power.
You can see a few other things that are "Hot in Run". 1994 is not like 1993 so disregard the Glow Plug Controller as it's ECM controlled. My bad for confusion over my 1993.
Now what do you have, now, in just the run position? Do you have a Service Engine Soon and Service Throttle soon light up for a bulb check after the key has been off for 30+ seconds?
Have you tried cranking in neutral?
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Landon730
Active Member
In run position I have service engine soon and just the normal lights nothing special. Tried testing crank fuse with key in start position with it in neutral and park and still have no power to crank fuse
ak diesel driver
6.5 driver
Need a full schematic of the ignition switch. Probably more than one power source to it.
The ign power sources "D" and "B" are tied to one fusible link. I believe these are a connector on the column itself. Keep in mind the neutral park switch will prevent cranking. You can probe the purple wire as I think the Neutral/Park switch is in the column. It's possible the relay that had burnt wires was part of an alarm. Again purple being for the starter. Now on some years the fuel pump will run if you crank in gear. So we have power to the ignition switch and through the run part of the switch to ECM (via the Service Engine Soon lamp on) and are missing both "crank" an signal to the starter. IMO This is pointing to the switch itself in Start unless both wires are damaged coming off the column. Possible the switch is out of adjustment and/or the "rod" from the key to the switch is bent in the column.
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Landon730
Active Member
Thats exactly what it seems like. It does everything normal like if you had it in gear kinda of cranking. Ill try to find that fusable link and test it
Wasn't done editing. Clearly the fusiable link is good or the ECM, via the SES lamp lit, wouldn't be on. Can you turn the switch backwards to "radio" and does the radio light up or power windows operate? This could tell if the switch adjustment or bent rod is in play. My 1993 gasser 1/2t POS had a bent rod.
Landon730
Active Member
So are you thinking the ignition switch then?
@Husker6.5 is as well. Note my thoughts on adjustment as well.
Landon730
Active Member
Ok Ill update yall as soon as I can get some time to work on it
Husker6.5
135' diagonal 16:9HD, 25KW sound!
Yes. My thoughts are that the ignition switch went bad on the Previous Owner, who then thought that he/she could rig up their own by-pass to the bad switch (your cut wires and disconnected terminals), but instead created a dead short (your burnt wires/fusible link(s) in the wiring looms) that they threw up their arms in surrender to.
Enter you.
We'll walk you through this no-crank situation, but it has to be done methodically and the first step in the process is verifying that there is proper voltage at the necessary terminals of the ignition switch for each key position and that the ignition switch itself is in proper adjustment to the actuating rod. If you have voltage there, then you start following the voltage path to the next point to measure at. When you get to none where there should be some, then you know your break is between the two. Finding shorts is a similar process using a continuity light.
Eventually, we will get those electrons flowing where they should be.
Also, you really should get yourself the GM Chassis Book (4 volumes on paper) or CD ROM (internet access to GM library) for your model year or newer truck. Those wiring diagrams are FAR superior to the incomplete crap in the Haynes/Chilton manuals and the Factory diagnosis and troubleshooting flow charts are invaluable.
Enter you.
We'll walk you through this no-crank situation, but it has to be done methodically and the first step in the process is verifying that there is proper voltage at the necessary terminals of the ignition switch for each key position and that the ignition switch itself is in proper adjustment to the actuating rod. If you have voltage there, then you start following the voltage path to the next point to measure at. When you get to none where there should be some, then you know your break is between the two. Finding shorts is a similar process using a continuity light.
Eventually, we will get those electrons flowing where they should be.
Also, you really should get yourself the GM Chassis Book (4 volumes on paper) or CD ROM (internet access to GM library) for your model year or newer truck. Those wiring diagrams are FAR superior to the incomplete crap in the Haynes/Chilton manuals and the Factory diagnosis and troubleshooting flow charts are invaluable.
Landon730
Active Member
Ok when I turn the switch to "radio" the windows will roll up and down and the radio comes on.
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Husker6.5
135' diagonal 16:9HD, 25KW sound!
The switch appears to be in adjustment. Now you need to check for proper voltage at all the terminals of the ignition switch in each key position.
I would suggest that the switch is in adjustment then.
Check the purple wire "a" on the column plug for voltage in crank. If no then try again with the shifter in neutral. Ign switch or P/N safety switch is the question thus the attempt in neutral.
Landon730
Active Member
Do I have to unbolt the column and to get access to it?
Landon730
Active Member
Ok Ill try that tomorrow evening and see what I've got. I'm assuming that if I don't have power in correct positions I need to try changing the ignition switch? If there is power where it should be I still have a needle in the haystack?
One step at a time. We suggest the above by you is correct. Case in point we are proving switch is bad. Not thowing parts at it.
I am guessing the park nutral is a mechanical block of turning the ign switch. You can confirm by trying to turn key gently to start in gear. I will look at my 1993 and confirm. Old tech vs. new stuff confuses me sometimes.
I am guessing the park nutral is a mechanical block of turning the ign switch. You can confirm by trying to turn key gently to start in gear. I will look at my 1993 and confirm. Old tech vs. new stuff confuses me sometimes.
Landon730
Active Member
NEW INFO... I changed the ignition switch cause there was actually a spare laying around. Still no fix... I took my test light up to the ignition switch and I CANNOT get power to purple crank wire. With it in park and neutral I still have nothing. I'm wondering if its the gear safety switch? Also there is another plug on the very bottom of the column that looks like its missing wires. Ill take some pictures and post it. Not sure what its for but I can twist it and it clicks.
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Do you have 12v at "D" and "B" the red wires on the ignition switch connector wires? The other switch that isn't installed you can manually move to crank: plug it in and retest. Assuming you still have SES light and radio lighting up?