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1970 Challenger electrical gremlins
Posted By: 1969RR
1970 Challenger electrical gremlins - 05/27/10 01:59 AM
Hello again! Sorry, but this is gonna be long! Just got the car all back together. Let me tell you a bit about the build. It is a 383, 4 speed. Most everything new. I installed a new engine harness, the modified one for electronic ignition. The balast is the 4 prong style. Everything under the hood is new, electrical wise. I had the dash out. Installed a new under dash harness (ralley guage). I checked all the guages with a 9v battery, all "swept" like they should. I bought a new ammeter guage and limiter from Dash Worx. Now for the issue! MOST everything works, lights normal, wipers normal, fan normal, dash lights, oil pressure guage works, even the reverse light works! When I turn the key "on" the amp guage does nothing. No movement at all. Gas guage, nothing, temp guage, nothing. Like I said, the only guage that works is the oil guage. Car started!! But, will not turn off with the key. Unhook neg bat cable, shuts off. I check and have power at all 4 prongs at the resistor with key off! Both wires on the back of the alternator have power with key off. When I got the car, it would shut off normally. I have since done all this work! Where do I start troubleshooting??? Again, Sorry this is sooooo long! Thanks in advance!! Jeff
Posted By: superwrench
Re: 1970 Challenger electrical gremlins - 05/27/10 04:57 AM
The only wire at the alternator that should have 12 volts with the key off is the big main black one to the stud.
The other two (blue and green on my '71) are field wires from the regulator.
I think the reason the car won't shut off when you turn the key off is because the coil circuit or the ballast is still gettingpower from somewhere.....MAYBE the same place those other alternator wires are getting it too.
Start trouble shooting the ignition switch,ballast and regulator circuits...I think there-in lies the problem.
Posted By: HealthServices
Re: 1970 Challenger electrical gremlins - 05/27/10 08:16 AM
Just happen on this post late, not that I go on this part of the forum much, but my bet currently without checking much is the alternator regulator area.
Unplug the dark blue wire with the tracer from the alternator. Check the wire for voltage. It should not have voltage with the key off. If it has voltage look in the direction of the ignition switch. If it does not have voltage, leave unplugged and go to next step.
Check the other field wire at the alternator for voltage also check the resistor for voltage. If there is voltage remove wire (alt/reg side) from resistor check the wire for voltage, if there is still voltage remove the alternator and have it tested.
Quote:
Unhook neg bat cable, shuts off.
Normally speaking the car would still run if you were to remove the battery cable as the alternator would still supply voltage to the electrical system. It did not in this instance, further pointing the finger at the alternator area.
Of course this is all assuming the harness was correctly installed. 
Posted By: 70Coronet500Vert
Re: 1970 Challenger electrical gremlins - 05/27/10 10:58 AM
You have a switched lead and a constant source power lead switched somewhere. The ignition needs a switched lead or the car will not turn off.
Posted By: 1969RR
Re: 1970 Challenger electrical gremlins - 05/27/10 05:04 PM
Hello! Again, thanks for the help! Went home at lunch, unhooked voltage regulator, STILL power at all 4 wires at the resistor block. Unhook each of the wires at back of alternator, both have power to the wire, even un-hooked. When I stated that I can un-hook the NEG cable and car will shut off, this is with the key in the off position, so I'm assuming that this kills the power at the resistor block and shuts off the power to the coil?? You think my problem is an underhood wire issue, or ignition switch? I just hate to have to take the column all back apart! Just my luck tho. Anyone have any ideas concerning the ammeter. As I said, it does not move at all when I turn key off & on...I do have to turn the key to ON to get the turn signals to work, so it must be switching power off and on..or am I thinking incorrectly? Thanks again! Jeff
Posted By: HealthServices
Re: 1970 Challenger electrical gremlins - 05/27/10 05:13 PM
Let me shut down my computer and restart. Even though I'm on google Chrome the computer is popping up virus alerts about this site every 45 seconds. Getting very frustrating. Hopefully I can come back...
Posted By: 1969RR
Re: 1970 Challenger electrical gremlins - 05/27/10 05:51 PM
Hey Allen, I know that feeling! Mine did that last night. I couldn't do anything. Was able to fix today luckly! Don't know what is going on with the virus issue! Talk to ya later! Jeff
Posted By: HealthServices
Re: 1970 Challenger electrical gremlins - 05/27/10 06:39 PM
Unplug each wire at the resistor block until you find out which wire is hot.
Posted By: 1969RR
Re: 1970 Challenger electrical gremlins - 05/27/10 07:18 PM
Allen, They are ALL hot all the time, plugged in or not. What should I look at that is feeding all 4 wires? Thanks, Jeff
Posted By: HealthServices
Re: 1970 Challenger electrical gremlins - 05/27/10 07:21 PM
Each one of the wire ends are hot when unplugged from the resistor? Not asking to check the resister itself but the wires themselves when disconnected.
Posted By: HealthServices
Re: 1970 Challenger electrical gremlins - 05/27/10 07:29 PM
Follow the resister wires (one is brown, and the other is blue with a tracer) to the bulkhead connector. Disconnect it at the bulk head and check the firewall connector for voltage where these two wires would normally go in, they should be dead with the ignition off.
Posted By: superwrench
Re: 1970 Challenger electrical gremlins - 05/27/10 07:31 PM
Resistor gets it's power from the ignition switch.
Should be bluewire. This wire is also spliced into the Alt/Reg circuit.
I'm suspecting the ignition switch itself, or the wires in the harness maybe not in the right cavity at the switch or bulkhead.
Frustrating ain't it?
Posted By: HealthServices
Re: 1970 Challenger electrical gremlins - 05/27/10 08:00 PM
The harness should look something similar to this. Click the picture after you hit the attachment for a larger view.
Posted By: HealthServices
Re: 1970 Challenger electrical gremlins - 05/27/10 08:36 PM
You mentioned that you still have voltage at the resistors when the regulator is disconnected and the key is ‘off’. This tells me the Brown wire is still hot (battery voltage) with the key off still. Please double check this as this does direct you to something mis-wired or a issue at or near your ignition switch as others have indicated. This also means more work.
Make sure your wiring is the same at the diagram as this is what I am going by.
And to hopefully keep you from going crazy going back and forth between two pages, I colored the wires and pasted the two pages together. Unfortunately it is a little big.
Posted By: 1969RR
Re: 1970 Challenger electrical gremlins - 05/28/10 01:22 AM
Hello! Did some more troubleshooting tonite after work. Allen, thank you, for the wiring diagrams! I disconnected the connector from the ignition switch, as I'm doing this, I hear "clicking"By the glove box, the relay "clicks", According to the wiring digrams this is the "key in buzzer" relay. With this plugged in, everything under the hood has power, BUT, as soon as I take the key completely out of the tumblers, ALL the power is gone under the hood, car shuts off normally. Why is the key causing the continuity? IF I turn the car off, leave key in, it will stay running. If I shut car off, then remove key, it will shut off normally... Remember, I am using an underdash harness from Y1, it said it is like the 1971 and this relay is the horn relay..??? Does this relay even need to be plugged in? Everything works without it. I don't have the "key in" buzzer anyway, or a horn for that matter! AND, what about the VOLT meter, it does nothing (it is brand new) is it possible to hook it up backwards, the red and black wire?? Would it matter?? The alt is not charging also. Boy, this has been a learning experience, and I couldn't have done it without all you guys!! A BIG thank you!! Jeff
Posted By: HealthServices
Re: 1970 Challenger electrical gremlins - 05/28/10 03:59 AM
I don't know if it is too many questions or they are jumbled together, or what, but I cannot follow. Maybe all of them.
Quote:
Hello! Did some more troubleshooting tonite after work. Allen, thank you, for the wiring diagrams!
You are welcome I will try ton answer what questions I can.
Quote:
I disconnected the connector from the ignition switch, as I'm doing this, I hear "clicking"By the glove box, the relay "clicks", According to the wiring digrams this is the "key in buzzer" relay.
It is normal for it to click.
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With this plugged in,
The key, the connector, or the relay? Or all of them?
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everything under the hood has power, BUT, as soon as I take the key completely out of the tumblers, ALL the power is gone under the hood, car shuts off normally. Why is the key causing the continuity? IF I turn the car off, leave key in, it will stay running. If I shut car off, then remove key, it will shut off normally...
Sounds like an issue with the ignition assembly.
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Remember, I am using an underdash harness from Y1, it said it is like the 1971 and this relay is the horn relay..???
I don't follow on this part at all, what are you saying?
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Does this relay even need to be plugged in? Everything works without it. I don't have the "key in" buzzer anyway, or a horn for that matter! AND, what about the VOLT meter, it does nothing (it is brand new) is it possible to hook it up backwards, the red and black wire?? Would it matter?? The alt is not charging also. Boy, this has been a learning experience, and I couldn't have done it without all you guys!! A BIG thank you!! Jeff
I don't think you should be worried about so many things at one time. I think you should worry about one thing at a time.
I do think 
you should concentrate on the Ignition not shutting off first.
I'm not sure if I understand the above statements but it sounds like you have an issue with the ignition assembly.
Posted By: superwrench
Re: 1970 Challenger electrical gremlins - 05/28/10 04:24 AM
I may be out to lunch...BUT...take a lookat that wiring diagram real close. Notice that the dark blue wire(with tracer) that is coming out of the key-in relay circuit is going directly to the resistor/regulator/alternator splice. They all share that same blue wire.
Now..take a look at the red wire to that relay. It's going back to the ignition switch.
Could it be the switch is hooped,or as i mentioned before, maybe the wires at the switch connector are not installed right from the manufacturer and the key-in system is supplying voltage to the coil etc as soon as the key is plugged in?
Just my thought
Posted By: HealthServices
Re: 1970 Challenger electrical gremlins - 05/28/10 04:35 AM
Maybe, I wonder what happens if you unplug the key-in warning buzzer then? Let me circle the item I think you are talking about.
I can't seem to follow anybody today.
Posted By: HealthServices
Re: 1970 Challenger electrical gremlins - 05/28/10 05:11 AM
You are talking about these areas right?
Posted By: superwrench
Re: 1970 Challenger electrical gremlins - 05/28/10 02:26 PM
Exactly. And further more, notice the "oil warning" lamp or circuit is tied in with that blue wire. The OP said his oil guage was the only thing that worked. H-m-m-m
Posted By: 1969RR
Re: 1970 Challenger electrical gremlins - 05/28/10 03:06 PM
Hello again everyone. Sorry some of this runs together, I'm trying to type as fast as my brain is coming up with ideas....ain't workin'! Anyway, Yes, Allen, if I unplug the key in relay, the car shuts off normal. With this plugged in, I have power at the resistor, coil, etc....where it's not supposed to be. With the relay un-plugged, power is normal at coil, resistor etc..I think somehow the key is causing the "ground". If I pull the key out of the column as I'm turning the car off, it will shut off normally. When I bought the harness from Y1, it came with instructions that stated "this harness uses different relay than a 1970, it is included" Superwrench, the red wire at the relay has power when the key is in, no power with the key pulled out..With the relay unhooked, the oil gauge still works tho. I just don't have VOLT or GAS gauge working. Again, Thank you all for helping me!! Jeff
Posted By: superwrench
Re: 1970 Challenger electrical gremlins - 05/28/10 03:41 PM
Just a question...might sound silly...BUT....did you happen to get a '71 harness and are using it in a '70 car?
My digging here shows some differences in circuits.
Just trying to isolate the gremlin.
Posted By: 1969RR
Re: 1970 Challenger electrical gremlins - 05/28/10 04:57 PM
Superwrench, I got the harness from YearOne, it came with a note (I wish I could find the note) stating this harness is also used in a 1971, and the only difference is the relay, so one is supplied with the harness. I wonder if anyone else has used this harness and ran into this issue. I'm gonna give Y1 tech a call also. Take care! Jeff
Posted By: HealthServices
Re: 1970 Challenger electrical gremlins - 05/28/10 05:34 PM
Quote:
Hello again everyone. Sorry some of this runs together, I'm trying to type as fast as my brain is coming up with ideas....ain't workin'! Anyway, Yes, Allen, if I unplug the key in relay, the car shuts off normal. With this plugged in, I have power at the resistor, coil, etc....where it's not supposed to be. With the relay un-plugged, power is normal at coil, resistor etc..I think somehow the key is causing the "ground". If I pull the key out of the column as I'm turning the car off, it will shut off normally. When I bought the harness from Y1, it came with instructions that stated "this harness uses different relay than a 1970, it is included" Superwrench, the red wire at the relay has power when the key is in, no power with the key pulled out..With the relay unhooked, the oil gauge still works tho. I just don't have VOLT or GAS gauge working. Again, Thank you all for helping me!! Jeff
Sounds like the power is some how back feeding thru the key buzzer. Wonder if it has anything to do with the diode here
Posted By: 70Coronet500Vert
Re: 1970 Challenger electrical gremlins - 05/28/10 06:44 PM
Quote:
if I unplug the key in relay, the car shuts off normal. With this plugged in, I have power at the resistor, coil, etc....where it's not supposed to be. With the relay un-plugged, power is normal at coil, resistor etc..I think somehow the key is causing the "ground". If I pull the key out of the column as I'm turning the car off, it will shut off normally.
You are picking up the relay coil with the key in, it woudl seem you have a wire landed on the wrong contact of the relay.
Posted By: HealthServices
Re: 1970 Challenger electrical gremlins - 05/28/10 08:40 PM
Quote:
Quote:
if I unplug the key in relay, the car shuts off normal. With this plugged in, I have power at the resistor, coil, etc....where it's not supposed to be. With the relay un-plugged, power is normal at coil, resistor etc..I think somehow the key is causing the "ground". If I pull the key out of the column as I'm turning the car off, it will shut off normally.
You are picking up the relay coil with the key in, it woudl seem you have a wire landed on the wrong contact of the relay.
I wonder if it does it with the door open or closed?
From what I understand the way it is suppose to work is... If the key is in the ignition + the door is open. the buzzer is suppose to sound.
Apparently you are not getting the buzzer and the car continues to run. Maybe there is a short or there is a mis-wire at the buzzer causing the red wire there to go directly to the blue wire with the tracer.
Posted By: 1969RR
Re: 1970 Challenger electrical gremlins - 05/29/10 09:54 PM
Hey guys, The only diffreence I can see from my old harness to the new Y1 harness, is at the door jamb switches, my old harness only had 1 plug in, the new harness has 2. I had to buy new jamb switches. As for the door question.....if doors are shut, car turns off normally....if open, will not shut off and have power at coil, resistor etc...I cannot hear a "key buzzer" nor do I remember the diode in this harness. Still chasin'!! Take care!! Jeff
Posted By: HealthServices
Re: 1970 Challenger electrical gremlins - 05/29/10 10:55 PM
Quote:
Hey guys, The only diffreence I can see from my old harness to the new Y1 harness, is at the door jamb switches, my old harness only had 1 plug in, the new harness has 2. I had to buy new jamb switches. As for the door question.....if doors are shut, car turns off normally....if open, will not shut off and have power at coil, resistor etc...I cannot hear a "key buzzer" nor do I remember the diode in this harness. Still chasin'!! Take care!! Jeff
It is at this section where you are having the issue. remove and repair this buzzer or replace it. This will at least get the buzzer working. if not the ignition problem. If the ignition problem continues remove and replace the diode. If it is not in the buzzer this diode is wired into the harness it could be in backwards. If you are lucky it is 1/4 inch in size.
This is where your problem is! With the key in the red wire is hot to the buzzer. the relay is suppose to ground the buzzer side of the buzzer, but is instead back feeding the power to the Dark Blue wire with the tracer (ignition wire)
Posted By: superwrench
Re: 1970 Challenger electrical gremlins - 05/30/10 12:55 AM
Exactly what I was wondering about the doors when open!!!
WOW!! what a cluster$%#@!!!!
Posted By: 1969RR
Re: 1970 Challenger electrical gremlins - 05/31/10 02:26 AM
Hey guys! And everything under the dash is new!! Guess that doesn't make it right tho! I tried swapping out the relay, still the same issues. Where is the diode located? I honestly do not remember anything like this when I was installing the dash and wiring.
Posted By: HealthServices
Re: 1970 Challenger electrical gremlins - 05/31/10 02:36 AM
I'm just going by the wiring diagram. I only had the buzzer out one time many moons ago. If no one chimes in, I would look at the buzzer itself for the diode first. If not there it should be within 2 inches of where the buzzer plugs in.
Posted By: HealthServices
Re: 1970 Challenger electrical gremlins - 05/31/10 02:39 AM
A diode is very small, look for something like this...
Posted By: HealthServices
Re: 1970 Challenger electrical gremlins - 05/31/10 02:50 AM
And this is just my thinking but if you already swapped the relay out with a known good one, I think the diode may be on backwards or in your case not on there at all.
Most diodes I've seen though are on the unit they are trying not to have back feeding thru.
Posted By: Hemi Allstate
Re: 1970 Challenger electrical gremlins - 11/02/11 06:25 PM
I am trying to help a friend with this same scenario. 70 Challenger and Year One harness. Same problem with the open door preventing engine shut off.
I removed the relay and the engine shuts off like it should.
Anyone else have this problem? Any updates from the OP on this?
Where is the buzzer located? Where can I buy one?
Thanks,
Mark
Posted By: 1969RR
Re: 1970 Challenger electrical gremlins - 11/02/11 07:15 PM
Hello! As I'm reading this, I'm thinking...man, this sounds like the problem I was having...wait, I am the OP! Odd problem. Took a phone call to tech line to figure out. I just un-hooked the door relay and it works fine. The relay is over next to, hooked to the glove box liner. As long as it's un-hooked, works fine. Jeff
Posted By: Hemi Allstate
Re: 1970 Challenger electrical gremlins - 11/02/11 07:53 PM
Quote:
Hello! As I'm reading this, I'm thinking...man, this sounds like the problem I was having...wait, I am the OP! Odd problem. Took a phone call to tech line to figure out. I just un-hooked the door relay and it works fine. The relay is over next to, hooked to the glove box liner. As long as it's un-hooked, works fine. Jeff
Jeff,
What was the cause of your gauges not working? The fuel and oil pressure gauges do not work on this car.
I did remove the relay and like you said it works fine. I just wasn't sure if there would be any unwanted side effects to doing that.
I am glad that you were reading this.....again!
Thanks,
Mark
Posted By: HealthServices
Re: 1970 Challenger electrical gremlins - 11/02/11 07:56 PM
As mention it is either missing the diode or the diode is on backwards on the relay
Posted By: Hemi Allstate
Re: 1970 Challenger electrical gremlins - 11/02/11 08:00 PM
Quote:
As mention it is either missing the diode or the diode is on backwards on the relay
Well there is no diode on the relay and I have not yet seen the buzzer to see if it is there. Would it possibly be mounted to the buzzer?
Thanks,
Mark
Posted By: HealthServices
Re: 1970 Challenger electrical gremlins - 11/02/11 08:01 PM
or inside the buzzer maybe?
Posted By: HealthServices
Re: 1970 Challenger electrical gremlins - 11/02/11 08:05 PM
or...
a diode was not installed on the reproduction harness causing it to back feed power!
Posted By: Hemi Allstate
Re: 1970 Challenger electrical gremlins - 11/02/11 08:14 PM
Quote:
or...
a diode was not installed on the reproduction harness causing it to back feed power!
Allen, I suspect that this is the correct answer!
The under dash on this car is tight quarters as it had AC on it, and I haven't laid eyes on the buzzer yet.
Thanks
Mark
Posted By: 1969RR
Re: 1970 Challenger electrical gremlins - 11/02/11 08:49 PM
Hello, HealthServices helped me BIG time on my issue. I don't have that diode either. The reproduction harnesses must not use it. Everything else works fine on mine since I removed the relay. My trouble was actually the opposite or yours. Mine would run as long as the door was open. I could care less about the buzzer, so I just left it out. Worked fine since. Jeff