grounding gremlins

[Tom Sinon 70]

I'm a new member , found this site by accident and had to join .
Anyhow I have a 70 Duster , 225 slant six VL29C0B and i'm thinking that I have one or many bad ground connections , gas gauge is inaccurate , new dash lights don't work as well as the headlights ( the gauges do work ) I removed the gauge cluster to fix a speedo problem and put in the new dash lites while I was there . of course this didn't all appear at the same time , the gas gauge was never right , bla bla bla ...anyhow i'd like to know where are the ground locations so I can go through and clean them up , any help would be great . Thanx

 

[67Dart273]

Might not just be grounds, generally:

Bulkhead connector problems read the MAD article:

Catalog

Voltage drop in the functional path from battery to various loads causes problems not the least of which is OVER charging because of voltage drop to the voltage regulator (for the alternator)

The dash cluster HAS NO ground other than mounting screws. It is HIGLY recommended to ADD a ground from a ground point on the cluster via pigtail wire bolted to the dash frame or column support

"What was wrong" with my 67 cluster:

1...PC circuit board connector pins broken or loose, here's a thread by someone else

Printed circuit pins repair

2.....Also in the above thread is repair of the guage voltage limiter contacts/ socket

3....The guage stud nuts can corrode. Loosen/ tighten them to scrub them clean and consider replacing with "real" nuts

4....The senders can be wrong resistance, stuck, corroded in case of gas gauge, and repop ones just plain seem to be inaccurate. There has been HUNDREDS of threads on this problem............

Hey Del, Look what I found!!! An original Miller Gauge tester!!!

Homemade gauge test tool, C-3826

 

[RedFish]

The only 2 bulbs in the inst' panel that have a ground wire are PARK and OIL. those get a ground through their remote switches. All other bulbs are chassis grounded through the hardware that holds the panel in the dash ( just like most everything else on these cars ). If the shift indicator and radio light dont work either, the dimmer rheostat on the headlight switch is suspect. Or maybe a blown fuse? The 1 fuse that doesn't have power at either end before headlight switch is pulled to first detent ( park lamps ). That's the lighting fuse, marked inst I think.
OEM fuel sender might need nothing more than a new float. they do go bad/get fuel in them. If a previous owner has put a reproduction sender in the tank, the fuel gauge will be wrong. There is a extra electronic item called "meter match" that will let you program the gauge/sender relation so aftermarket sender works closer to accurate.

 

[Tom Sinon 70]

Might not just be grounds, generally:

Bulkhead connector problems read the MAD article:

Catalog

Voltage drop in the functional path from battery to various loads causes problems not the least of which is OVER charging because of voltage drop to the voltage regulator (for the alternator)

The dash cluster HAS NO ground other than mounting screws. It is HIGLY recommended to ADD a ground from a ground point on the cluster via pigtail wire bolted to the dash frame or column support

"What was wrong" with my 67 cluster:

1...PC circuit board connector pins broken or loose, here's a thread by someone else

Printed circuit pins repair

2.....Also in the above thread is repair of the guage voltage limiter contacts/ socket

3....The guage stud nuts can corrode. Loosen/ tighten them to scrub them clean and consider replacing with "real" nuts

4....The senders can be wrong resistance, stuck, corroded in case of gas gauge, and repop ones just plain seem to be inaccurate. There has been HUNDREDS of threads on this problem............

Hey Del, Look what I found!!! An original Miller Gauge tester!!!

Homemade gauge test tool, C-3826

that's interesting I never had 12 volts to the coil and I think I should have 12 v at the coil

 

[67Dart273]

that's interesting I never had 12 volts to the coil and I think I should have 12 v at the coil

No the coil (OEM) is supplied through the ballast resistor. THE KEY SIDE of the ballast is branched off to the VR, and this would be the point I was referring to "suffers the drop."

Coil voltage will vary "depending"

If you have breaker points, example:

Key on, engine stopped, battery at full charge, coil + will measure

........Same as battery if points are open

..........With points closed, coil+ will vary from about 8 to 10 or so.
"Running" coil + voltage will vary from about 10-11 to as much as 12, when system is charging at 14, and depending on engine RPM

 

[Tom Sinon 70]

No the coil (OEM) is supplied through the ballast resistor. THE KEY SIDE of the ballast is branched off to the VR, and this would be the point I was referring to "suffers the drop."

Coil voltage will vary "depending"

If you have breaker points, example:

Key on, engine stopped, battery at full charge, coil + will measure

........Same as battery if points are open

..........With points closed, coil+ will vary from about 8 to 10 or so.
"Running" coil + voltage will vary from about 10-11 to as much as 12, when system is charging at 14, and depending on engine RPM[/QUOTE that's what I thought

 

[Tom Sinon 70]

that's what I thought

 

[Tom Sinon 70]

Ok so if we can get back to the original question , where are the MAJOR ground points

 

[67Dart273]

Ok so if we can get back to the original question , where are the MAJOR ground points

In regards to what? You expect me to go through every service manual from 62 to 76 and painstakingly eke out the diagrams for hours and hours WITH NO PAY and then tell you what they are?

Be more clear and specific in your question

The headlights are grounded with a pigtail from the connectors to the rad support. This varies over the years.

Turn signal/ park / tail lights are grounded variously by socket mounting and individual pigtails. Marker lights.....68 and later are grounded by pigtails from the lamps.

I've already mentioned that the cluster as an assembly is grounded by the mounting screws. Radio, ditto. Heater blower motor has a pigtail that screws to a grounding screw over by the right hand kick panel.

VR is grounded by mounting screws as is ignition ECU if used.

Starter is grounded to the block, battery is grounded to block, with a "too small" jumper to the body



****. ****!!! Go to MyMopar.com Download yourself a factory service manual. go through the diagrams. See what you find. Then come back here and ask questions.

http://www.mymopar.com/downloads/servicemanuals/1970_Plymouth_Service_Manual.zip

http://www.mymopar.com/downloads/servicemanuals/1970_Charger_Coronet_Service_Manual.zip

 

[RedFish]

It's a chassis ground system. The nuts and bolts that hold it together create a metal to metal current path which serves as ground wire.
2 actual main ground wires are one from chassis/firewall to engine block, another from engine block to battery negative post. There are a few other short ground jumpers where plastic fixtures, etc., don't create a path. You likely saw one example at steering column mounting studs. Adding ground wires everywhere you like can't hurt anything. It can help in cases like the inst' panel. If you want to test the panel while it dangles from its harness connectors... you'll have to attach a ground jumper wire.

 

[Tom Sinon 70]

thanks for your advice , sorry if I ruffled any feathers