Author Topic: dash light(no power) issue  (Read 392 times)

Offline javakm70cuda

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dash light(no power) issue
« on: April 08, 2019 - 12:50:59 pm »
I have been playing with an issue for over a week on my 70 gran coupe and getting beat every time. I think I have a 71 wiring harness too because it has the door buzzer and horn relay as one piece. I have the dash light hooked into the Orange three female outlet which my 70 manual says is correct. For the life of me I cannot figure out why it does not have power at that outlet. Anyone run into this before. Any other places in wiring I could connect the dashlight. I noticed the light under the dimmer switch does not come on either. Also is dashlight suppose to come on when door opens?




Offline 70chall440

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Re: dash light(no power) issue
« Reply #1 on: April 08, 2019 - 01:35:53 pm »
First place to look is your fuses and make sure everything is functioning, second is at your dimmer switch (the dash one), all dash light power comes from it.
Current Mopar
70 Challenger RT 440-6 EFI, 73 Cuda 416-6 EFI
05 Hemi Durango, 01 Ram 4x4, 14 Ram 2500 4X4, 10 PCP Challenger 6 spd RT, 01 Viper GTS ACR, 52 B3B w/330 Desoto Hemi, 70 Hemi RR (under const)
Past Mopars
9 x Challengers. AAR Cuda, 4 RR, 2 GTX, 4 Chargers, etc... (too many to list)

Offline javakm70cuda

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Re: dash light(no power) issue
« Reply #2 on: April 08, 2019 - 10:55:24 pm »
So I looked at instrument fuse and no power. Followed orange wire to the column connection. I found there is no wire coming from my starter and ignition switch(column). Not cut off or anything, just not there. It is a 4speed car if that makes a difference. Does the instrument fuse power the dimmer switch is my question. I assumed power for instrument fuse came from somewhere else other than the column. Normally when you open your door and car is not running does the dash light come on or is it powered only when key is turned back or to on position?
Any help appreciated.

Offline 70chall440

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Re: dash light(no power) issue
« Reply #3 on: April 08, 2019 - 11:27:51 pm »
Yes, your dome light should come on when either door is opened.

The instrument light fuse gets power from the main power wire. In other words, you should be able to turn on your lights (to include your instrument lights) without the key in or on. If you do not have power to the fuse, something is broken or disconnected.

Were they working previous or is this a new build?

Being a 4spd car doesn't matter on the electrical side except for the reverse light and the safety neutral switch (if connected)
Current Mopar
70 Challenger RT 440-6 EFI, 73 Cuda 416-6 EFI
05 Hemi Durango, 01 Ram 4x4, 14 Ram 2500 4X4, 10 PCP Challenger 6 spd RT, 01 Viper GTS ACR, 52 B3B w/330 Desoto Hemi, 70 Hemi RR (under const)
Past Mopars
9 x Challengers. AAR Cuda, 4 RR, 2 GTX, 4 Chargers, etc... (too many to list)

Offline javakm70cuda

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Re: dash light(no power) issue
« Reply #4 on: April 09, 2019 - 08:10:08 am »
When you say "main power wire". Which wire are you referencing? Are you referencing the red wire going to the column. In past the red wire to column got hot(before my time), but that has been fixed to not happen again. Dash light plugged into orange 3 female outlet in pic below
« Last Edit: April 09, 2019 - 08:23:01 am by javakm70cuda »

Offline 70chall440

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Re: dash light(no power) issue
« Reply #5 on: April 09, 2019 - 11:19:32 am »
Do you have a wiring diagram? The fuse block receives power from a red 12 gauge wire coming from the battery. This feed line emanates from a junction of 6 wires. The bottom line is that the fuse block must be powered to all fuses. If other things are getting power in the fuse block, then there is some issue with the fuse connections. Try by passing the fuse with a jumper to see if your lights work.
Current Mopar
70 Challenger RT 440-6 EFI, 73 Cuda 416-6 EFI
05 Hemi Durango, 01 Ram 4x4, 14 Ram 2500 4X4, 10 PCP Challenger 6 spd RT, 01 Viper GTS ACR, 52 B3B w/330 Desoto Hemi, 70 Hemi RR (under const)
Past Mopars
9 x Challengers. AAR Cuda, 4 RR, 2 GTX, 4 Chargers, etc... (too many to list)

Offline javakm70cuda

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Re: dash light(no power) issue
« Reply #6 on: April 09, 2019 - 06:04:30 pm »
I believe I understand what your saying, but when I look at back of fuse block the instrument fuse is partitioned off from the others. Please let me know if I misunderstood what you were trying to explain. Because it is not connected to other fuse power I am having trouble figuring out where the power should feed from.
« Last Edit: April 09, 2019 - 06:09:37 pm by javakm70cuda »

Offline 70chall440

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Re: dash light(no power) issue
« Reply #7 on: April 10, 2019 - 12:08:22 am »
We are basically saying the same thing. I looked at a wiring diagram when I responded last time and saw a 12g red wire supplying power to the fuse panel, I could be mistaken about which wire provides the feed but I do not believe I am based on the diagram. Bottom line, the light circuit is generally not running through the ignition switch, rather it is connected directly to a battery source.

Do you have a power probe? they are invaluable in doing what you are trying to do.
Current Mopar
70 Challenger RT 440-6 EFI, 73 Cuda 416-6 EFI
05 Hemi Durango, 01 Ram 4x4, 14 Ram 2500 4X4, 10 PCP Challenger 6 spd RT, 01 Viper GTS ACR, 52 B3B w/330 Desoto Hemi, 70 Hemi RR (under const)
Past Mopars
9 x Challengers. AAR Cuda, 4 RR, 2 GTX, 4 Chargers, etc... (too many to list)

Offline javakm70cuda

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Re: dash light(no power) issue
« Reply #8 on: April 10, 2019 - 10:39:13 am »
I do have a 70 original manual with a wiring diagram but my wiring to me looks to be out of a 71 car when I look at fuse block.

Looked at diagrams here also

https://forum.e-bodies.org/electrical-and-audio/11/colored-wiring-diagrams-70-cudachallenger/1349/

No wiring diagrams that I can see show a red feeding the instrument fuse(the one I show in pic with red box). Unless power is being fed through the dimmer switch and back to fuse I am a bit lost. Where or how is the red wire connecting to instrument fuse(e2-18 O). on fuse block as shown in pic there is no connection unless there is a wire in middle of plastic that is broken. 

I do understand though the ignition is not feeding power. Wires only meet there to feed automatic car column light which I do not have.

« Last Edit: April 10, 2019 - 10:41:04 am by javakm70cuda »

Offline 70chall440

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Re: dash light(no power) issue
« Reply #9 on: April 10, 2019 - 12:33:26 pm »
Looking at the diagram on page 8-97, the light switch is getting power (I believe) from a feed group (red circle). This comes directly from the battery (I believe).

In other words, you need to determine if the switch is getting power and then trace in which ever direction you need to (to the power source if no power at the switch) or to the lights if there is power.
Current Mopar
70 Challenger RT 440-6 EFI, 73 Cuda 416-6 EFI
05 Hemi Durango, 01 Ram 4x4, 14 Ram 2500 4X4, 10 PCP Challenger 6 spd RT, 01 Viper GTS ACR, 52 B3B w/330 Desoto Hemi, 70 Hemi RR (under const)
Past Mopars
9 x Challengers. AAR Cuda, 4 RR, 2 GTX, 4 Chargers, etc... (too many to list)

Offline javakm70cuda

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Re: dash light(no power) issue
« Reply #10 on: April 11, 2019 - 11:37:26 pm »
So I am at this conclusion. If I disconnect my dimmer switch and place the headlights on and connect the wires together I have power to the fuse and dashlight come on. If the system is suppose to turn on when the door opens without key on then I could not tell you how. Either way my dimmer switch is the issue in my case.

Offline 70chall440

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Re: dash light(no power) issue
« Reply #11 on: April 12, 2019 - 12:50:46 am »
Only the dome light should come when the door is open as it has a connected power source and negatively activated.

At least you found out the dimmer switch is bad.
Current Mopar
70 Challenger RT 440-6 EFI, 73 Cuda 416-6 EFI
05 Hemi Durango, 01 Ram 4x4, 14 Ram 2500 4X4, 10 PCP Challenger 6 spd RT, 01 Viper GTS ACR, 52 B3B w/330 Desoto Hemi, 70 Hemi RR (under const)
Past Mopars
9 x Challengers. AAR Cuda, 4 RR, 2 GTX, 4 Chargers, etc... (too many to list)