1970 Chrysler 300 - No Power

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wayne Wagstaff

wayne Wagstaff

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My 300 would just lose total power while I was driving. I took it into a few shops, spent good money and the problem continued. I replace all of the wiring with a Painless replacement set, which was anything but painless! The car has been running well until today except for one small issue. Sometimes when I turn the key on the starter kicks over then I lose all my electrical power. I have to get out and disconnect the battery and connect it again. I then can start it and drive away and it will not happens for days. I have a battery switch on the battery for disconnecting the power. I had the problem today, before I went out. Drove the car to 2 locations and say 20 miles. I then went to go home and I was driving along the road and just getting onto a bridge and the engine shut down. I had it towed home. At home I turned the battery off and on and it works again. Any ideas?
 
If you used the Painless #10127 harness, be sure to download the latest manual, as the Acc wiring destructions were updated.

We could use some more info. What are you using for ignition? Stock, or after market like MSD? What alternator and what is the output while fielding? Have you checked to see if there is a draw on the battery (or a voltage drop over night)? What wiring harness? Did you ensure to sand off of your ground pads for a good connection? What starter relay (3 or 4 post) is it new or old?
 
wayne Wagstaff said:
My 300 would just lose total power while I was driving. I took it into a few shops, spent good money and the problem continued. I replace all of the wiring with a Painless replacement set, which was anything but painless! The car has been running well until today except for one small issue. Sometimes when I turn the key on the starter kicks over then I lose all my electrical power. I have to get out and disconnect the battery and connect it again. I then can start it and drive away and it will not happens for days. I have a battery switch on the battery for disconnecting the power. I had the problem today, before I went out. Drove the car to 2 locations and say 20 miles. I then went to go home and I was driving along the road and just getting onto a bridge and the engine shut down. I had it towed home. At home I turned the battery off and on and it works again. Any ideas?
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A little off topic, but my nephew just picked up a pretty loaded 300 destined to be parted. Let me know if you need any parts and I'll pass it on to him.
 
Scody21 said:
If you used the Painless #10127 harness, be sure to download the latest manual, as the Acc wiring destructions were updated.

We could use some more info. What are you using for ignition? Stock, or after market like MSD? What alternator and what is the output while fielding? Have you checked to see if there is a draw on the battery (or a voltage drop over night)? What wiring harness? Did you ensure to sand off of your ground pads for a good connection? What starter relay (3 or 4 post) is it new or old?
Click to expand...
 
The car is totally stock. It looks to me like there is a breaker that trips and killing the power resets it.
 
wayne Wagstaff said:
The car is totally stock. It looks to me like there is a breaker that trips and killing the power resets it.
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I’ve had that happen with poor connection to the battery. I’d start with the simple free things first.
 
wayne Wagstaff said:
The car is totally stock. It looks to me like there is a breaker that trips and killing the power resets it.
Click to expand...

You did say that there’s a new painless harness in it correct? If you used the 10127 harnes I noted, don’t think there is a beaker. It’s all in a mini fuse panel.
 
Was the wiring replaced as a result of what is happening; or was the wiring replaced, and now this is happening?
 
xLURKxDOGx said:
I’ve had that happen with poor connection to the battery. I’d start with the simple free things first.
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Agreed.... he makes no mention of battery cable condition or the existence of proper ground straps (to body) of car. Certainly could be just a bad main cable.
 
royslead said:
Was the wiring replaced as a result of what is happening; or was the wiring replaced, and now this is happening?
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It happened before while I was driving. I would pull over, try to start the car and no luck. I would get towed home then start the car and drive it into the garage. Until yesterday, after replacing the wiring harness, it has only been happening when I went to start the car. Yesterday it was as I was driving. I have no idea where a relay would be, unless it is in my charging gage. It seems like ALL of the power goes through the charging gage then out from there. I have thought about putting in a wire to bypass the charging gage but not sure if that would create a problem.
 
If I remember, yes, everything went through the ammeter (charging gauge) on Chrysler's for many years. The replacement harness - what all did it include? Was it just underwood, was it under dash, both, etc? Is anything, wire related, still original? Do you have proper engine to body and battery to body grounds?
 
royslead said:
If I remember, yes, everything went through the ammeter (charging gauge) on Chrysler's for many years. The replacement harness - what all did it include? Was it just underwood, was it under dash, both, etc? Is anything, wire related, still original? Do you have proper engine to body and battery to body grounds?
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Can I run a parallel wire around the ammeter? Maybe just by pass it altogether or replace it.
No old wire except maybe the tail light or door wiring where Painless did not supply it. The grounds are the grounds I have had for the last 25 years or more. They are clean.
 
IMG_1156.jpg
I had a similar problem with a loose connection to the starter selenoid. car died. no start. played with (green?) wire to starter selonoid and viola! check the simple.

My buddies 300. It's the Hurst car they used to promote at races...with the shifter on a platform
 
wayne Wagstaff said:
Can I run a parallel wire around the ammeter? Maybe just by pass it altogether or replace it.
No old wire except maybe the tail light or door wiring where Painless did not supply it. The grounds are the grounds I have had for the last 25 years or more. They are clean.
Click to expand...

You can bypass the ammeter, but do not do it with a parallel circuit. You should, I believe, be able to just disconnect the wiring to the ammeter and connect those wires together Some of the other recommendations about checking solenoid wiring, etc are good advice as well. Also, if you haven't, check the bulkhead wiring for corrosion/ poor connections, etc.
 
I had very similar issue on 67 cuda. 273. Elec ign and mostly clean original harness. Altho it is getting brittle/cracking. I would check the ign switch itself also. Is it in dash (hopefully).
Not sure if abodies are wired the same as yours. Large gauge black(I think) wire goes to bulkhead connector may need to be replaced/upgraded. Check bulkhead for melted wires/plastic.
Good luck. Beautiful car.
 
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