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1970 challenger wiring

Posted By: otter440

1970 challenger wiring - 09/12/23 11:41 PM

i am doing 1970 challenger went with all new wiring in the car i have pretty much evrything working but the dash lights and headlamps. i have tried different h/l switches. dash dimmer switch, and floor dimmer switch. for some reason i have no power to the orange wires in the dash and no headlamps. the marker lights,taillights and parklamps all work fuse is good. I am baffled any suggestions thanks
Posted By: stumpy

Re: 1970 challenger wiring - 09/12/23 11:55 PM

Are your grounds all good? You Should have power to one terminal on the high low floor switch with the headlights on. with the HL switch plugged in but not installed you should be able to see which terminals supply 12v out. Dash lights have their own fuse fed by the dimmer.
Posted By: otter440

Re: 1970 challenger wiring - 09/13/23 12:11 AM

my grounds are good. i have no power to the fuse for the dash lights
Posted By: TJP

Re: 1970 challenger wiring - 09/13/23 02:07 AM

Originally Posted by otter440
my grounds are good. i have no power to the fuse for the dash lights

have you checked the thumbwheel dimmer for the dash lights. If at either extreme it could shut beer the power off
Posted By: EW1BH27

Re: 1970 challenger wiring - 09/13/23 12:52 PM

Just to clarify, you have no power to the circled orange connector?

Attached picture Orange plug.png
Posted By: otter440

Re: 1970 challenger wiring - 09/13/23 01:12 PM

That is correct
Posted By: 6PakBee

Re: 1970 challenger wiring - 09/13/23 01:39 PM

I don't have a '70 available but looking at the wiring diagram for a '71 it seems straightforward. Black wire from the headlight switch to the dimmer switch. Tan wire from the dimmer switch to the fuse block. Fuse. Orange wires to dash lights. Follow the trail. Good luck.
Posted By: TJP

Re: 1970 challenger wiring - 09/13/23 04:23 PM

Originally Posted by otter440
i am doing 1970 challenger went with all new wiring in the car i have pretty much evrything working but the dash lights and headlamps. i have tried different h/l switches. dash dimmer switch, and floor dimmer switch. for some reason i have no power to the orange wires in the dash and no headlamps. the marker lights,taillights and parklamps all work fuse is good. I am baffled any suggestions thanks


While the diagram that EW1BH27 posted is helpful, you really need the schematic for the entire car or at least those showing the dashboard/dimmer switch forward. You can try to get by with out it but it really saves time>
the entire service manual is available here for FREE FREE Manuals
I print out the sections needed, tape them together if necessary, and strongly encourage a box of assorted colored pencils to trace the wires.
I would go after each circuit separately Starting with the headlights. It may take a little bit to familiarize yourself with the way the schematic(s) were done but it is pretty easy. Optionally buy one of the laminated full size color coded schematics.

1. Do you have power at the center terminal of the dimmer switch? that power comes from the headlight switch. No power? check the other two terminals just for giggles. I've seen several mis-wires on "NEW" harnesses as well as bad crimps.
a). Check the headlight switch to verify power is present at the terminal that feeds the H/L's when they are on. Be aware some cars use separate 12v feeds for the H/L's and other lights. the largest wire is normally headlights.
b) If you don't have power at the output to the dimmer, using a wiring diagram for YOUR car work your way back to find the source of that power. If there are connectors along the way, checking each connector and the in and out terminals.

keep us posted beer
Posted By: EW1BH27

Re: 1970 challenger wiring - 09/13/23 05:25 PM

Here's the other 1/2 of my posted schematic

Attached picture Color Rallye wiring2.png
Posted By: spk2go

Re: 1970 challenger wiring - 09/13/23 06:39 PM

Orange wire is powered through the ignition switch, may want to try jumping the wires there.
Posted By: TJP

Re: 1970 challenger wiring - 09/14/23 01:43 AM

Originally Posted by spk2go
Orange wire is powered through the ignition switch, may want to try jumping the wires there.


That would have nothing to do with the power for the head or dash lights. it may be an indicator lamp for the ignition switch
Posted By: firebreather

Re: 1970 challenger wiring - 10/23/23 03:03 PM

Originally Posted by TJP
Originally Posted by otter440
i am doing 1970 challenger went with all new wiring in the car i have pretty much evrything working but the dash lights and headlamps. i have tried different h/l switches. dash dimmer switch, and floor dimmer switch. for some reason i have no power to the orange wires in the dash and no headlamps. the marker lights,taillights and parklamps all work fuse is good. I am baffled any suggestions thanks


While the diagram that EW1BH27 posted is helpful, you really need the schematic for the entire car or at least those showing the dashboard/dimmer switch forward. You can try to get by with out it but it really saves time>
the entire service manual is available here for FREE FREE Manuals
I print out the sections needed, tape them together if necessary, and strongly encourage a box of assorted colored pencils to trace the wires.
I would go after each circuit separately Starting with the headlights. It may take a little bit to familiarize yourself with the way the schematic(s) were done but it is pretty easy. Optionally buy one of the laminated full size color coded schematics.

1. Do you have power at the center terminal of the dimmer switch? that power comes from the headlight switch. No power? check the other two terminals just for giggles. I've seen several mis-wires on "NEW" harnesses as well as bad crimps.
a). Check the headlight switch to verify power is present at the terminal that feeds the H/L's when they are on. Be aware some cars use separate 12v feeds for the H/L's and other lights. the largest wire is normally headlights.
b) If you don't have power at the output to the dimmer, using a wiring diagram for YOUR car work your way back to find the source of that power. If there are connectors along the way, checking each connector and the in and out terminals.

keep us posted beer


Thank you, I will download these manuals. I have no power to either the headlights or the marker lights, I'm trying to figure it out.
Posted By: IMGTX

Re: 1970 challenger wiring - 10/23/23 03:35 PM

Originally Posted by firebreather


Thank you, I will download these manuals. I have no power to either the headlights or the marker lights, I'm trying to figure it out.


When Checking for Voltage at the plug do not use a VOM connected to both sides of the plug. Run one lead of the VOM to the battery.

You could have a bad ground which looks like no voltage at the plug, very common. If you ground the VOM at the battery when you check for Positive voltage at the plug you will get an accurate reading as to whether or not there is Positive voltage at the plug.

I always confirm my ground to my test gauge/light is good before I test for voltage.

Hope it helps.
Posted By: Cab_Burge

Re: 1970 challenger wiring - 10/23/23 05:39 PM

I think that Dodge change some of the wring harnesses on both E bodies from 1970 to 1971 and later, maybe not scope twocents
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