Brake Warning Light Wire Firewall Opening

[Cav73]

The wire that goes from the e-brake switch on my 73 Challenger is currently routed through the same firewall hole as the hood release cable. This how the restoration shop I used left it. The release cable grommet is not yet seated in the hole; I can't do that yet as the e-brake switch wire is preventing it.

This may be a result of compromises made during restoration, as we changed this car from automatic to manual using parts from another Challenger. The hood release cable is brand new, and I believe this car did have one originally.

I'm pretty sure I'm going to have to cut the e-brake switch wire and reconnect it after rerouting. However, does anyone know where the wire is supposed to enter the firewall? Could there be another hole just for it, that somehow I do not see, up above the e-brake assembly? Or is it really supposed to connect somewhere under the dash?

Thanks! This is one of the various mysteries I still have to solve...

 

[Vaanth]

The wire to the brake warning lamp switch routes through the bulkhead disconnect via cavity 24. Inside the car, where the wire enters the cavity from the instrument cluster warning lamp, it joins with the wire to the parking brake switch. From cavity 24 under hood, the wire runs to the brake warning lamp switch.

The wiring connections are shown in the factory service manuals wiring diagrams. If you don't have the 1973 Doge service manual, a two volume set, are available at MyMopar.com via the following links. The linked are compressed PDF zip file.

1973 Dodge Chassis Service Manual
1973 Dodge Body Service Manual

 

[Cav73]

Vaanth, thank you! So the wire is supposed to go to the fuse box (bulkhead disconnect if I understand you correctly), cavity 24, and not directly through any opening in the firewall. I have the manual, but frankly I'm still learning how to read those wiring diagrams properly and was not at all sure about this. I will check the wiring paths based on this and make any correction necessary. On both sides of the firewall. I will post the result asap...

 

[Vaanth]

Vaanth, thank you! So the wire is supposed to go to the fuse box (bulkhead disconnect if I understand you correctly), cavity 24, and not directly through any opening in the firewall. I have the manual, but frankly I'm still learning how to read those wiring diagrams properly and was not at all sure about this. I will check the wiring paths based on this and make any correction necessary. On both sides of the firewall. I will post the result asap...

The bulkhead disconnect is behind the fuse box, so behind it. The fuse box clips to the bulkhead. The other side is in the engine compartment where all the wiring there connects to go inside.

Following are a couple of quickly highlighted screenshots showing the bulkhead cavity 24, etc.

From the engine compartment diagram page, 8-128:

From the instrument cluster diagram page, 8-131 (or similar on 8-138):

 

[Cav73]

Vaanth, thanks for these wiring charts. Unfortunately, I was way off. I got back under the dash today. The wire I was looking at was not the e-brake wire, instead it is attached to a switch on the frame for the clutch pedal, above the clutch pedal return spring. I am going into my manual this evening to figure this out. Currently, the wire goes from that switch into the engine compartment through the hole for the hood release cable, then goes up to the driver side fender where it attaches to the same "box" (not sure of the correct terminology) where several other wires attach, including one of the battery cables.

I can't guarantee that my harness is fully accurate. The car certainly has started fine after reassembly and I believe all the lights work, but I have the steering column out and can't test anything just yet to be sure.

I have the Mopar Performance orange box ignition installed, and an electric fan. All this, and the overall engine harness, transferred to this car from a 72 I had. which became my primary parts car.

I will be going through all the engine compartment wiring asap to solder any squirrely connectors.

Thanks for your help, I'm sorry I was so far off base starting this thread.

 

[Challenger RTA]

Short version.

 

[Vaanth]

Vaanth, thanks for these wiring charts. Unfortunately, I was way off. I got back under the dash today. The wire I was looking at was not the e-brake wire, instead it is attached to a switch on the frame for the clutch pedal, above the clutch pedal return spring. I am going into my manual this evening to figure this out. Currently, the wire goes from that switch into the engine compartment through the hole for the hood release cable, then goes up to the driver side fender where it attaches to the same "box" (not sure of the correct terminology) where several other wires attach, including one of the battery cables.

I can't guarantee that my harness is fully accurate. The car certainly has started fine after reassembly and I believe all the lights work, but I have the steering column out and can't test anything just yet to be sure.

I have the Mopar Performance orange box ignition installed, and an electric fan. All this, and the overall engine harness, transferred to this car from a 72 I had. which became my primary parts car.

I will be going through all the engine compartment wiring asap to solder any squirrely connectors.

Thanks for your help, I'm sorry I was so far off base starting this thread.

The switch at the clutch pedal is the clutch safety switch. It grounds the starter relay when the pedal is depressed to allow the starter relay to be engaged to crank the engine. The wire routes through a separate dedicated hole in the firewall. The wire is green and has a molded grommet on it to seal in the dedicated hole. From there, under hood, it runs along the inner fender apron and connects, with a bullet connector, to another green wire that continues to the starter relay and connects to the "G" (ground) terminal as shown in post #6.

Although you have the switch, the following image shows one with the correct molded grommet on the wire:

The firewall hole for the wire is in the corner of the firewall and fender apron, below the grommet for a manual windshield washer hoses, or a Caplug if not so equipped. The following image shows where it comes through the firewall. In this case, the wire and grommet has been painted with the engine compartment:

If your car was not an original manual transmission car, the hole will not be open from the factory. And if it has not been drilled open by whomever installed the manual setup, there will be a small dimple there showing where to drill for it.

Following are two more images showing the wiring inside and at the firewall to supplement post #6:

 

[Cav73]

Bingo, mystery solved. Thanks guys. Yes, my 73 was an automatic to begin with, and my restorer put the pedal assembly from my 72 manual car into it. They did not drill out that hole you discuss above, so I will look for it. I will drill it out if I can get to it. Hopefully I won't have to find an alternate place to drill. I will have to disconnect the wire at the starter relay or cut it and reconnect to route it correctly. At least I know what it is now, much appreciated!

While I was under the dash today, I disconnected the clutch rod and installed a brand new clutch rod boot, and reconnected the rod back together. All in all a successful day, that much closer to starting it up again.