my car is live! I mean 12v live!

[mopar56]

So my son and I are coming near to starting up his 70 Duster that has been sitting in a barn for years and now that the mechanical is done we put in a fresh battery to see what works and doesn't, we discovered he had no lights so I checked the bulkhead connector and the 12v red main in was a mess, some one had pulled it out and jammed a 18 gauge wire into the spade connector then jammed it into the bulkhead, any way, fast forward... we did the "MADD BYPASS" ( I have done this before on a couple other cars ), figuring this would solve all problems we tried it again but still no lights then when testing with my " power probe meter " it slipped of the wire I was testing and touched the fire wall and I was astonished to see the fire wall in fact the entire car, hood, fenders, doors everything is 12v, how could this be? one thing I am thinking is we just installed a mini starter from a Dakota to clear the headers, do they isolate different from the old starter? maybe the main lead from the relay to the starter isn't isolated properly? BTW the wipers and blower work fine, also the brake lights only work when you press the clutch down at the same time as the brakes?, could be a ground issue there, maybe it needs an exorcism! lol

 

[67Dart273]

...... when testing with my " power probe meter " it slipped of the wire I was testing and touched the fire wall and I was astonished to see the fire wall in fact the entire car, hood, fenders, doors everything is 12v, how could this be? ............l

Geez slow down, LOL

Where were the two probes of the meter?

One was obviously on the firewall, where was the other?

If you are going to say "the battery" make sure you were not on the positive post!!

 

[mod5v]

And the later mini starter is wired the same as the early boat anchor starter.

 

[mopar56]

I was using a " power probe" that's the brand very nice and expensive meter the negative cable was on the negative battery terminal the tool is the positive probe as for the mini starter I wondered if it used a insulated spacer or something? Thanks

 

[67Dart273]

Sum ting Wong!!!

No idea what you did there, but it's not "a spacer" LOL

 

[mopar56]

OK I will report with my findings

 

[PocketAces]

If the negative battery terminal is connected to the engine, and the engine is grounded to the body, then you cannot have a potential difference (voltage) between the negative battery terminal and the body. Either the meter was on the wrong battery post or the battery cables are hooked up backwards.

Check your battery cable connections at both ends, verify the correct polarity, and check your engine to firewall ground wire.

 

[mopar56]

Battery cables and tester hooked up correctly however I do not have a engine to chassis ground only a ground from battery cable to engine I should add a chassis ground as mentioned earlier barn find car that was sitting years and many missing parts what gauge of wire should I use for that?

 

[PocketAces]

Proceed with caution. If everything you are saying is correct, then you have 12 volts shorting to the body and the only reason sparks aren't flying is because the body is not grounded to the battery. When you add the engine to body ground you will complete the circuit and sparks should fly.

Not sure on the gauge. 10, maybe 12. Should be stranded wire.

 

[PocketAces]

Check the voltage between the engine block and the firewall. If you see 12 volts, then don't hook up the ground wire until you figure out why.

 

[mopar56]

Pocket aces thank you! Just needed chassis ground I added a 10 gauge chassis ground now things are better the chassis is no longer 12v and the brake lights work the rear signals work and the r/f signal but the left front signal is still nfg but there is a bit of a dog's breakfast of wiring going to that so I will correct that also I have running lights but still no head lights or dash lights I think the headlamp switch is nfg because there is no power going from the tan wire to the "instr" fuse as well as no high or low beams so I will replace it lastly still no start I have power to the starter relay but nothing coming out so I guess I will replace that to...arrgghh.....

 

[mopar56]

OK got all the lights working, had a bad connection at the back of the dash causing l/f signal to not work so that's fixed and found a ground behind the battery box that wasn't hooked up causing the headlamps to not work, still don't have dash lights though or power to the Inst circuit in the fuse box so still leaning towards a nfg light switch

 

[RedFish]

head light switch sends power from its terminal marked B2 to that inst fuse when switch pulled on to park lamp position. The turn the knob dimmer rheostat feature is the most common failure. I found it simple enough to place a jumper over that rheostat and get bright as possible lighting at all times. A whole new switch is like 13 bucks so that's the more common/practical fix. New switch will have a male spade for additional ground wire too. Another ground there may not be needed now that you've added one somewhere else.

 

[mopar56]

Thanks Redfish, I may just try your jumper idea as the switch up here in bend over and pay Canada is over 30 bucks CDN, and this car has been nickle/dimeing my kid dry, lol, did you just take the jumper from the tan wire terminal B2 on top of the switch and tie it directly to the wire coming from the fuse box? I really don't care if the dimmer works personally I never touch mine in any of my vehicles I just turn to max and leave it there.

 

[RedFish]

Thanks Redfish, I may just try your jumper idea as the switch up here in bend over and pay Canada is over 30 bucks CDN, and this car has been nickle/dimeing my kid dry, lol, did you just take the jumper from the tan wire terminal B2 on top of the switch and tie it directly to the wire coming from the fuse box? I really don't care if the dimmer works personally I never touch mine in any of my vehicles I just turn to max and leave it there.

The jumper I soldered in went directly on the switch. One contact has a hole through it. That one was pulled out and trimmed off in front of the hole. The other contact is directly beneath at the center of the rheostat. Jumper through hole and down to other. I no longer have a pic of what I did.
There is probably other ways to do it. I'm thinking the way you suggest would keep the dash lights on at all times, thus a battery killer.
Some owners have simply cleaned that rheostat to get it conducting again.

 

[mopar56]

OK thanks again I power up the fuse circuit this morning with my "power probe" tester and the dash lit up I decided to just order the switch it's the right thing to do .

 

[Killer6]

OK thanks again I power up the fuse circuit this morning with my "power probe" tester and the dash lit up I decided to just order the switch it's the right thing to do .

Just spotted this,LOL!! Yeah, obvious signs of no ground on the body, I have seen resistance from panel to panel on these cars(Mopars) across spotwelded sections, including
the cowl section to firewall/bulkhead, etc., the interior lights were taking ground away from an interior mounted orange box unit on a 'Cuda I was working on...ran a wire between
panels.........................

 

[mopar56]

Update...replaced the head light switch and repaired one ground in the r/f marker/signal light and all is fixed!, one last small issue though, the reverse lights will come on if I jumper the connector at the trans switch, and the switch is new and it worked when I tested it on the bench prior to trans installation but the reverse lamps don't light when in reverse, I believe the ball in the reverse switch isn't going in far enough to create the ground needed to loop the switch is it possible that the reverse gear just isn't going in all the way because I am static shifting it as I haven't had the car running yet?

 

[Killer6]

Update...replaced the head light switch and repaired one ground in the r/f marker/signal light and all is fixed!, one last small issue though, the reverse lights will come on if I jumper the connector at the trans switch, and the switch is new and it worked when I tested it on the bench prior to trans installation but the reverse lamps don't light when in reverse, I believe the ball in the reverse switch isn't going in far enough to create the ground needed to loop the switch is it possible that the reverse gear just isn't going in all the way because I am static shifting it as I haven't had the car running yet?

I believe the plastic "shuttle" activates the b/u lamps, the "ball" grounds the wire from the starter relay allowing it to engage when powered by the key. I have run into this
before, on FWD units too, very frustrating when You're trying to kick a job out. I've had to double-up gaskets between the switch & the case to get some to work & get them
down the road.

 

[mopar56]

Thanks for the reply killer now you say double the gasket on the switch but I would have thought the opposite because the ball dent us depressed when the reverse arm sweeps across it therefore it would make me think it isn't deep enough in the Trans and a gasket would pull it away more making it worse?