Wiring help for my 1970 Sport Sat

Moparfiend · Feb 10, 2019

I am consolidating a few threads and will be going to use this thread for ongoing help for electrical wiring issues that I am having.

Your help is greatly appreciated!

Ok so right now I have a lot of issues. My guages are not working nor my rear lights. My headlights are operational. All my fuses are intact.

Previously I found a pink line that was burned up. I removed the driver kick panel to inspect the 6 way connector. It looks good. I have found however that the line that was burned up did not route through the 6 way but went from pink to black and routed along side but not with the encased wires from the harness. I am trying to identify this wire. The origin of this wire is not known but I believe it was directly from the fuse box pink set.

BeepBeepRR · Feb 10, 2019

That pink wire goes to the overhead dome light, if I remember correctly.

The blue wire in that connector is the fuel sender.
Yellows go to door switches for the dome/console lights.

Moparfiend · Feb 10, 2019

Thanks PB OK I had to rip up glued carpet to trace the wire. It ran all the way to the trunk and is the trunk light lol. Not sure why it burned up. But that question is now solved.

OK no dash electrical or rear tail lights. Looks like I have to get into the dash darn it. I have to drop the steering column to do that as well. Fun fun fun.

BeepBeepRR · Feb 10, 2019

Im sure you have a wiring schematic. If not download the files here. http://www.mymopar.com/index.php?pid=27

oldbee · Feb 10, 2019

Don’t forget checking all grounds also.

BeepBeepRR · Feb 10, 2019

threewood · Feb 10, 2019

Moparfeind said:
Thanks PB OK I had to rip up glued carpet to trace the wire. It ran all the way to the trunk and is the trunk light lol. Not sure why it burned up. But that question is now solved.

OK no dash electrical or rear tail lights. Looks like I have to get into the dash darn it. I have to drop the steering column to do that as well. Fun fun fun.

Check the run carefully, especially if there is rust damage in the trunk area or behind the rear seat. Mine wasn't burned up but was grounded out from having the insulation rubbed off in the area of some rust. The fuse to mine was removed which shows there was an issue with it prior to me rebuilding it.

PurpleBeeper · Feb 10, 2019

You KNOW that pink wire shorted somewhere, so the easiest/cheapest way to deal with it is to just run a whole new wire, connect it on both ends & just leave that pink wire in there (un-hooked).
Gauges --> check for ground first. There should be a 6" black wire on the right/bottom of the steering column + I think one coming off the headlight switch. 2nd --> see if you have power going to the dash. 3rd --> replace the "voltage limiter" in the dash that drops the voltage down to 5volts (?) for the gauges (common Mopar problem)

Tail Lights --> run jumper ground wire to the side of the bulb sockets (to check for a bad ground) & repair if necessary. 2nd --> check for power at the sockets themselves & back track the power. I believe the tail lights are powered by the 6-pin connector behind the driver's kick panel.

HOPE THIS HELPS!

oldbee · Feb 10, 2019

My “old school” always have is a 20’ 14ga wire with alligator clips on both ends. Use it to jump 12v or from battery neg. as a known good ground to reach anywhere.

Moparfiend · Feb 10, 2019

Guys thank you. I have the factory manual and schematics. I couldn’t even if I wanted to reuse that pink trunk line lol. PB thanks for the suggestions!! I did look for voltage at the 6 way connector behind the kick. No voltage. This is why I am looking behind the dash. After I dropped the steering column and pulled the plastic dash off there is still a sheet sheet metal sub dash there block ease of access and visibility to all the wiring. Its a lot of fun lol

72RoadrunnerGTX · Feb 11, 2019

No voltage, park lamps on, at L7-18BK (black 18 ga wire) in the 6-way dash harness to rear body harness? Do you have front park lamps working? L7-18bk is a straight run to the headlamp switch.

Nacho-RT74 · Feb 11, 2019

on a side note... if ground is missed at cluster, gauges will burn because voltaje limiter won't open points to regulate down to 5 volts. Just in case you decide some test, BE SURE ground is reaching the voltage limiter before energize it

Moparfiend · Feb 11, 2019

72RoadrunnerGTX said:
No voltage, park lamps on, at L7-18BK (black 18 ga wire) in the 6-way dash harness to rear body harness? Do you have front park lamps working? L7-18bk is a straight run to the headlamp switch.

Hi 72RR headlights do work. Ground continuity at male black spade on PCB good. I see 12V on the red main power spade on the PCB.

72RoadrunnerGTX · Feb 11, 2019

Do you have front park lights? Headlight circuit is separate from parking/tail lights. Exterior lighting does not involve the cluster printed circuit board. The black wire in the 6-way rear body connector runs straight to the headlamp switch, to the same terminal the front park lights are connected. If front park lights work, with no power at L7-18BK in the 6-way connector, there is an open in the black wire L7-18bk between the headlight switch and the 6-way connector.

Nacho’s comment above about cluster grounding is referring to the gauge problem only, not the exterior lighting issue.

Moparfiend · Feb 11, 2019

72RoadrunnerGTX said:
Do you have front park lights? Headlight circuit is separate from parking/tail lights. Exterior lighting does not involve the cluster printed circuit board. The black wire in the 6-way rear body connector runs straight to the headlamp switch, to the same terminal the front park lights are connected. If front park lights work, with no power at L7-18BK in the 6-way connector, there is an open in the black wire L7-18bk between the headlight switch and the 6-way connector.

Nacho’s comment above about cluster grounding is referring to the gauge problem only, not the exterior lighting issue.

Hi 72 RR Understood. I have the dash and light switch out. All my exterior lights have been removed but I can measure the voltage at some of the exterior light plugs (at least the ones that have not been previously cut). Will try and do that tonight.

Moparfiend · Feb 11, 2019

No gauges no radio nuthing but the oil light in the ignition 1 position. No running lights no dash lights no dome light voltage.

It’s got to be something basic with all this not working.

Moparfiend · Feb 11, 2019

Is the voltage limiter mounted to the PCB in a can? Is there a better way to get to the PCB? Its a PITA!

Moparfiend · Feb 11, 2019

No voltage to n any contacts of this connector when headlights are on and ignition off.

72RoadrunnerGTX · Feb 11, 2019

For the light issue, at the headlight switch, check for battery voltage at B1 (16ga black with tracer) and B2 (18ga pink).
Should have battery voltage on both, if the headlights work now, B1 should have power.
If B2 is dead, there will be no park/tail lamps, check the fuse for stop and tail lamps.

Moparfiend · Feb 11, 2019

Well the good news is I think I found the problem.
The bad news is its a lot of missing connections. Over the years and a lot of Bubbtization lines were cut and spliced and not connected correctly or not connected at all or respliced with the wrong color wire. I found multiple wiring issues at both the dimmer switch and headlight switch. It totally explains the isses I have been seeing. These are the points of distribution from the schematic.
Now in order to fix it I can get a new harness or try and splice in the missing and chopped wires.
A new harness sounds nice but all that routing inside the dash which has piss poor access sounds like a lot of work. I know its the right thing to do but if the wires look ok I will work to splice in the right wires and try to use the right colors as to maintain the schematics accuracy.
Hopefully this solves most of the problems.

One question: where physically is the Voltage Limiter located? Is it on the PCB? Is it a metal can 3 prong device?

Wiring help for my 1970 Sport Sat

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