Orange instrument lamps, where do they get power?

[pfonda]

Yet another wiring question...where does the orange lamp feed get it's power from? All of the yellow accessory lights work just fine, but the orange fed ones don't seem to turn on. When should the orange fed lamps actually be on? Would these run through the dimmer, any maybe be a sign of a bad dimmer switch?

Thanks,

Peter

[dodj]

Yes. Dimmer switch is the first place I would look

[Bullitt-]

If some contact cleaner doesn't do the trick you may need Jim's service to rebuild the dash dimmer... https://jsrestorations.com/

[Burdar]

If some contact cleaner doesn't do the trick you may need Jim's service to rebuild the dash dimmer... https://jsrestorations.com/

Last I heard, he had some health issues and wasn't taking any new business.  He had a back log of things to get done that needed his attention.

[Chryco Psycho]

he is backlogged but he will help you

[pfonda]

I've got a replacement switch on the way, will see if that works. May try to send in the old one for a rebuild if the new one solves the problem.

Thanks

[pfonda]

Ok, circling back on this issue. Changed the dimmer switch out, still not working. Looking at the wiring diagrams a bit more, and knowing that if I plug in the instrument light connector to a hot 12V supply, they do turn on, I figure it's a matter of the current lamp feed not receiving 12V power at all. If you track the orange lamp line, it shows it comes from the ignition switch orange feed, but my ignition switch has no orange feed (although the mating connector near the bulkhead does have the double orange feed (per the wiring diagram). Any ideas on why my ignition switch doesn't have an orange feed? Is there another place I can tap in for power, like the yellow accessory connector (only has one green line connected as of now)?

Thanks

[Bullitt-]

not sure model & year you have but I think this would be the same on any ebody

I believe the power for dash panel dimmer comes from the headlight switch..Black wire??
You do not have to have the ignition on for the panel lights to work but do have to flip the headlamp switch (which has consonant power) to at least the middle position.



Look up you model & year here http://www.mymopar.com/index.php?pid=24

[pfonda]

If I have the parking lamps on, or flip the headlights on all the way, still no power to the instrument lights. If you trace the power through the parking switch (black) to the dimmer switch, there's then a tan line that runs to the bulkhead, and should connect to the orange feed there to power all the instrument lights...any other ideas on what to check?

[Bullitt-]

Well the Tan wire just goes to the fuse block which comes out as Orange
  Do you have power getting to the fuse?  Fuse is good? 

[pfonda]

5A fuse is good, replaced it and same results. One thought is that from here, the orange goes back through the main harness and first stop is the connector below, which feeds power to the radio, but has orange 12V return line that's not connected. If I provide 12V power to the orange at this junction, the instruments will power up, but this should happen automatically right?

[Bullitt-]

 providing power at the radio connection junction has only proved that the connection from there to the lamps is good.. What seems to be the problem is the connection from fuse block to the radio.

  Confirm you have checked for power on the Tan wire at the fuse block when headlight switch is on
   Confirm the Orange wire is on the output side of the fuse the Tan wire connects to and that power is present. (it's possible this was assembled incorrectly at the factory)
    In the schematic it does appear that the Orange wire goes directly to the radio connector so you should be able to get continuity from the fuse block, if not there is a break in that section.
 

[mopar jack]

make sure you have a good ground. If this is an E body you need the switch cluster bolted to the dash frame to complete the ground.

[pfonda]

Ok, so the tan line at the dimmer switch has power, there's power across the fuse to the orange wire, and then there's power at the orange connector that leads down to the radio. The 3 way orange connector, however, doesn't have power, any ideas how this can happen? Shouldn't the orange that is headed from the radio connector be the same line that's powering the 3 prong connector?

[jamesroney]

Ok, so the tan line at the dimmer switch has power, there's power across the fuse to the orange wire, and then there's power at the orange connector that leads down to the radio. The 3 way orange connector, however, doesn't have power, any ideas how this can happen? Shouldn't the orange that is headed from the radio connector be the same line that's powering the 3 prong connector?

Short answer is "yes."

But your problem is a little strange, and the wiring diagrams don't explain things very well.

What is supposed to happen is that you are supposed to be able to dim the instrument lights, and the radio illumination light.

The power STARTS at the headlight switch.  When you turn on the lights, it powers the black wire on the dimmer switch.  The dimmer switch takes the 12V feed from the black wire, and runs it thru a variable resistor and outputs 0-12 volts on the Tan wire.  The tan wire FEEDS a single isolated fuse in the fuse box.  The output of that fuse goes to the orange wire that goes to the radio illumination, where it splits, and feeds the 3 outlet distribution plug.

(note that the wiring diagram in the service manual calls the E2a-18O the "radio." This is wrong.  It is the "Radio lamp")
(also note that the orange wire from the ignition switch is not "from" the switch.  It feeds the Automatic column shift indicator lamp.  That's why it might be blank at the ignition switch connector.)


Try this:

1. ensure that you have 12V on the black wire. (turn on the headlight switch)
2. Measure the voltage on the "instrument" fuse.  Vary the rheostat on the dimmer and make sure that the voltage changes correctly.
3. If the voltage is a steady 12...something is back-feeding the circuit.

send an e-mail to jamesroney@yahoo.com if you need help.  If you are working on 1970 Challenger wiring...its fresh in my mind.