Re: No power at ignition switch
[Re: 1970RT]
#2493203
05/07/18 02:29 PM
05/07/18 02:29 PM
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Joined: Aug 2003
Posts: 43,007 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,007
Bend,OR USA
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Corrosion one some of the contacts, probably What year and brand of car ?
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: No power at ignition switch
[Re: 1970RT]
#2493845
05/09/18 02:27 AM
05/09/18 02:27 AM
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Joined: Aug 2003
Posts: 43,007 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,007
Bend,OR USA
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Yes, nothing happens when I turn the key. When I leave the key in the run position and jump the relay it starts and stays running.
Thanks for all of the suggestions everyone. I have tried them all with the exception of changing the ignition switch to no avail. I filed all of the contacts on the bulkhead connector as well as the connectors on the plugs. Did the same for all of the wires connected to the starter relay as well as the switch on the trans. I have another column I guess I will have to scavenge the ignition switch out and see if that works.
Do not ASS U ME anything when trouble shooting problems, never ASS U ME Especially on electrical problems Take the time to identify the problem starting as Robert already suggested, look for the actual cause ,don't throw parts at it Good luck, we are here to help There is no magic in fixing cars, NONE Now, get back to work finding the problem You can do this
Last edited by Cab_Burge; 05/09/18 02:28 AM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: No power at ignition switch
[Re: RapidRobert]
#2494525
05/10/18 10:03 PM
05/10/18 10:03 PM
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Joined: Mar 2005
Posts: 939 Metro Detroit
1970RT
OP
super stock
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OP
super stock
Joined: Mar 2005
Posts: 939
Metro Detroit
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when you say no start I am assuming you mean no crank? If so, have a helper hold the key to start & see if you have fire at the yellow wire "ign" terminal on the starter relay & if not, seperate the black bulkhead connector & reinstall it which might be enough to restore continuity in that connection between the two halves & also with your meter see if it is hot with the key held to start & if not then check the connector at the ign sw. if the yellow wire starter relay ign terminal is hot then pull the connector off of the male "grn" starter relay terminal & ground the SR terminal (not the wire/connector you removed from it) to ground & now see if it will crank & if so there is an open back to the trans NSS switch on the side of the automatic trans or the clutch pedal switch (iirc, not a stick guy)) if a stick. If it will crank but no start pull the yellow wire off of the "ign" terminal to disable the starter (keeps the battery from being run down) & with the key held to start see if the coil positive primary terminal & the ECU hot wire (usually red on OE) at the pentastar ECU connector is hot & if a 5 pin ECU/4 terminal "dual" ballast setup the red/green terminal must be hot also. that'd be a start. (Pun intended) Still no luck finding the problem. I checked for power at the yellow wire on the relay as suggested and there is power there. I then tried grounding the grn terminal on the starter relay and still nothing when turning the key. I disconnected the plugs from the bulkhead again and ran a small file in each of the terminal slots. I then pulled the bulkhead out of the firewall under the dash and checked and filed all of the terminals there again. I checked all ground wires, tried a new ballast and also another ignition switch and still nothing.
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Re: No power at ignition switch
[Re: 1970RT]
#2494602
05/11/18 01:00 AM
05/11/18 01:00 AM
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Joined: Jan 2003
Posts: 10,486 Freeport IL USA
poorboy
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 10,486
Freeport IL USA
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Here is how the power flows from the ignition switch to the starter relay, and then from the relay to through the park/neutral switch, and then from the relay to the starter. You can test the power with a volt meter or a 1 volt test light.
If you have power to the yellow wire from the ignition switch when the key is held in the crank position, and no power to the yellow wire at any other time, the ignition switch is working.
From the switch, the yellow wire goes through the bulkhead connector. If you have power to the yellow wire after the bulk head connector, the bulkhead connector is good.
After the bulk head connector, the yellow wire connects to the starter relay. If you have power to the yellow wire at the starter relay, everything up to that point is good.
For the starter relay to work, power to the small brown wire on the relay has to pass through the park/neutral switch on the trans. After the switch trans, the wire through the park/neutral switch goes to ground to complete the circuit. If the power can't pass through the park/neutral switch, due to the transmission not being in park or neutral, or because of a defective switch, the power can't reach ground and the starter relay won't power the starter. If you ground the wire that goes through the park/neutral switch with a test light, you will complete the circuit, the starter may function. If the starter functions when the wire to the park/neutral switch is grounded, suspect a defective switch, or poor wiring, or a poor ground after the switch (assuming the trans is in park or neutral).
If the relay is powered through the park neutral switch, the small wire going to the starter will be powered with battery voltage when the relay functions. If the wire going to the starter is powered when the ignition switch is in the crank position, everything up to and through the relay is working.
If the wire to the starter has power but the starter does not run, The problem may be the wire to the starter itself, or the starter itself. I have seen the two prong terminal on the starter go bad inside. It looks good, but does not pass power through it.
If the motor will turn when the starter relay is jumped (or bypassed), the wires to the starter are OK.
The system is not complex. You simply follow the power supply through the system. When you reach a point the power in no longer present, you look for the problem between where the power last was to where it ended. Gene
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Re: No power at ignition switch
[Re: Govierjr.]
#2499605
05/23/18 06:18 PM
05/23/18 06:18 PM
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Joined: Mar 2005
Posts: 939 Metro Detroit
1970RT
OP
super stock
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OP
super stock
Joined: Mar 2005
Posts: 939
Metro Detroit
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Just curious if you found the solution to your issue? Yep, just got it solved. It was as mentioned, the starter relay not getting a good ground to the body. Kind of strange though since I had removed and replaced it with the two other relays and then put the original one back on (when the others didn't work) that the car still wouldn't start. I would have thought with all of that that at some point contact would have been made with one of the relays. Plus, I had also wire wheeled the threads on the mounting bolts and ran a wire brush through the holes which didn't do anything. In frustration, I just gave the SR a tug to make sure it was bolted down tight (which it was) and the car started when I tried it. The car has started each time I have tried starting it since. Thanks to everyone for their input and suggestions, I appreciate it.
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