Strange electrical issue - V-code 70 RR
#3078112
09/17/22 02:25 PM
09/17/22 02:25 PM
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Joined: Jan 2007
Posts: 531 Charlotte, NC
Kowal
OP
mopar
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OP
mopar
Joined: Jan 2007
Posts: 531
Charlotte, NC
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I am helping a friend with a car that he just picked up. A 70 V-code, 4 speed, Road Runner which is probably best described as a one repaint survivor.
Doesn't run well, barely starts, wiring has been hacked in to multiple times...every harness, and I mean every.
To get started, we decided to replace the engine harness which had a clumsy modification to add a Mopar ECU, several areas of burnt insulation and was in very poor condition. I've modified new Mopar engine harnesses to add Mopar Electronic ignition many times, I am sure that I got it right and with solid connections (I checked multiple times as we ran into issues). While doing this, I noticed multiple hacks and splices to the headlight harness and the very poor way the neutral safety switch harness had been repaired at some time (at least 4 splices). So I cleaned up the connections, replaced two almost broken wire connections to the bulkhead plug, but left how it was done alone figuring I would come back to it.
We go to start the car and we end up with the situation where we turn the key and nothing happens. But here is the really odd kicker...we noticed that when the key is in run or start...THE CLOCK STOPS! The clock runs otherwise with the key off and in accessory mode. Also...no headlights or dome light at all.
As I said the headlight harness is original, and hacked. Since the car was brought to my friends garage he told me that he had a moment with it where it wouldn't turn over and he moved some harnesses around under the dash and it worked again!
I checked, the connectors to the column are tight and look fine. There are no burn marks or melted areas on the bulkhead connector. I did notice by putting a lighted borescope under the dash that it looks like the black wire to the altimeter gage has been repaired at some time, the red is fine. There are no signs of damage to the gage +/- posts.
So what could happen circuit-wise that putting the key in to run and start is so bad that the clock stops! Prior to messing with the harnesses the car did turn over but started only very inconsistently, battery is charged. What started as a 6-pack tuning exercise has turned in to a "turn the key and stand next to the fire extinguisher!"
THOUGHTS?????
Last edited by Kowal; 09/17/22 02:33 PM.
'69 Hemi Charger 500, ‘70 U code Challenger R/T (These and a bunch others at www.dkowal426.com) P.J. O'Rouke: "The old car ran perfectly, right up until it didn't."
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Re: Strange electrical issue - V-code 70 RR
[Re: Kowal]
#3078116
09/17/22 02:42 PM
09/17/22 02:42 PM
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Joined: Sep 2003
Posts: 19,485 north of coder
moparx
"Butt Crack Bob"
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"Butt Crack Bob"
Joined: Sep 2003
Posts: 19,485
north of coder
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get a wiring diagram for this car, and trace all the starter switch wires from the key to the engine's starter components. look closely for burnt, broken, or hacked wires and splices, and go from there. as i'm not seeing what you see, it sounds like a complete replacement harness for the whole vehicle would be a good idea. lacking that, you will have to trace each item's circuit from under the dash to under the hood to really see what kind of hackery has been done. i believe you will learn a LOT about wiring with this car.
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Re: Strange electrical issue - V-code 70 RR
[Re: moparx]
#3078118
09/17/22 02:51 PM
09/17/22 02:51 PM
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Joined: Jan 2003
Posts: 10,736 North Dakota
6PakBee
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 10,736
North Dakota
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Wow, something is really messed up. Typically the clock is fed from a power supply 'hub' that feeds multiple devices that are energized all the time. The fact that the clock is now tied to an ignition feed is a major problem. If it was just one thing I'd say troubleshoot and repair. But with the amount of work a "Tommy Tinker" has done previously, I'm with moparx that a complete new harness is in your future.
"We live in a time when intelligent people are being silenced so that stupid people won't be offended".
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Re: Strange electrical issue - V-code 70 RR
[Re: Cab_Burge]
#3078148
09/17/22 04:21 PM
09/17/22 04:21 PM
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Joined: Jan 2003
Posts: 5,445 So Cal
Sinitro
master
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master
Joined: Jan 2003
Posts: 5,445
So Cal
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I would buy new replacement harnesses for the engine, front lights and under the dash and swap them out now Cab is correct.. If the original wiring and harness has been hacked up, time for a new wiring system. Many times a car guy will come to me about an electrical problem, but I take a look and find multiple splices, crimp connectors, wire nuts, loose unconnected wire stubs so the only fix is a new wiring harness. Just my $0.02...
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Re: Strange electrical issue - V-code 70 RR
[Re: Sinitro]
#3078203
09/17/22 08:24 PM
09/17/22 08:24 PM
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Joined: Jan 2003
Posts: 15,434 Omaha Ne
TJP
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 15,434
Omaha Ne
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I would buy new replacement harnesses for the engine, front lights and under the dash and swap them out now Cab is correct.. If the original wiring and harness has been hacked up, time for a new wiring system. Many times a car guy will come to me about an electrical problem, but I take a look and find multiple splices, crimp connectors, wire nuts, loose unconnected wire stubs so the only fix is a new wiring harness. Just my $0.02... X3
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