My '67 coupe has the infamous "Red Wire problem".

I've had the car fail to start a couple of times. Everything goes dead, except for the horn, and wriggling the inboard firewall connector will resuscitate the car. On occasion I will get a faint burning wire smell inside the car when driving. All this points to the need for an enduring solution to the red wire problem, and soon.

I've considered taking the bulkhead connector apart and cleaning the contact at the red wire. But others have warned that the connector can be brittle. If it breaks then I'd be in deeper than necessary.

In a recent post about this topic, 65GGvert wrote: "I know that many will disagree with me, and that's ok, I get it. In a recent post you wrote this about If this was happening to my car, I'd run a piece of red wire from the red wire at the connector (or all the way from the horn relay red) and connect it either directly to the back of the connection on the fuse box, or on the connection at the circuit breaker for the headlight rollover motors on the driver's side kickpanel. You will never have the issue again. If you do it correctly, no one will ever see it, and you won't have to worry about a loose connection feeding the red wire to the cabin ever again".

This is exactly what I want to do. But in order to tackle this fix, I need specifics on exactly how to bypass the red wire connection at the firewall.

Last night I examined my car's wiring and am puzzled by the red wire that goes from the horn relay up to the firewall near the wiper motor. This wire has an inline fuse installed. See pic below. Is this the factory red wire setup?


This red wire goes up to the firewall area, merging into the wiring harness near the wiper motor. Note that the front wiring harness was replaced by a previous owner, evidenced by "M & H" stickers on the harness where it meets the bulkhead connectors.


So, to my questions:

1. Where specifically do I connect the new bypass red wire at the horn relay?
2. Where specifically do I connect the new red wire inside the car? Should I connect it to the circuit breaker for the headlight rollover motors? Or it is better to go to the back of the fusebox? Which is easier, or preferred? Where do I find the headlight rollover circuit breaker? And where exactly on it should the new red wire be connected?
3. What sort of connectors do I need to solder onto each end of the new red wire?
4. How do I disconnect the old red wire that now runs through the inboard bulkhead connector at the firewall? Do I just disconnect it from the horn relay and tape it up out of the way?

Thanks in advance for your help!

 

that red wire is for your AC

 

I think the concept is to bypass that trouble some firewall connector with a new wire to take the loads i dont see why you cant leave the Existing in place.
Add a terminal block, relays and get a well functioning system going. See madelectrical
com it will answer your questions.

 

I am almost positive there a GM service bulletin to by pass the fuse block for the red wire

 

i think old dodges had this problem. You just drill through a blank spot on the firewall connector and run new wires.

 

I did this on my 66 as a preventative as I take her on road trips lasting a week or more. What your doing is running a parallel, if indirect, path to power the fuse box. On mine it was convenient to run a 10 gauge wire from the battery terminal on the alternator (you can use the horn relay too as electrically there connected) with a 30amp inline fuse back, into the cockpit. On the drivers side near the kick plate you will find the headlight motor breaker. Carefully remove the two wires going to the relay and identify which wire is hot. Memory fails me if the wire is hot all the time or only with the key in the run position. Either way the other wide will not be hot. Once identifying the hot wire, reconnect it the the headlight breaker where you removed it along with the new bypass wire. In the event of a firewall connector failure power will travel from the alternator/horn relay to the headlight breaker and on the the fuse block. Assuming you do not blow the 30amp inline fuse you added you would never know the red wire at the firewall connector failed, life is good.

 

I think he is describing a complete loss of electrical except the horn (feed directly from alternator) and not just a loss of ignition.

 

You are right John, Mother Mopar committed a similar sin in running system load through a bulkhead pin and through an ammeter. Chrysler folks strap a #10 between the alternator output lug and the starter relay which accomplished the same thing we are talking about here. 65GGvert's suggestion is spot on and on my list of things to do over the winter. I too have been put on the side of the road with this BS.

Dan

 

Click on the post, click "edit", then "delete" where a check box is located, and a final "delete post". You can do that for both your posts if you want to.

 

C2Dude I am so glad that you posted the above. I have experienced the "red wire" issue several times over the years. I installed the above suggestion yesterday so that it will be one less possible issue in the future. I ran my new wire from battery terminal on the alternator and it was hot all the time.

My wife and I leave for the Lancaster Ohio Corvette Gathering this Thursday.morning.

Safe travels and health to all,
Steve Stone (original owner, '63 triple black convertible, 604,000 miles)

 

Here's how I bypassed the red wire at the bulkhead connector of my '67 coupe.

Thanks to C2 Dude, Dan dplotkin and especialy 65GSVert for your suggestions on how to tackle this!

The first thing I did was to install a new battery cut-off switch (with the threaded green ****), which made it easy to apply and remove battery power as I tested things along the way.
Next I removed the hood latch assembly that sits above the bukhead connectors, which made it much easier to access the wiring to perform the splicing and insulating work.

1. Beginning state - I've exposed the red wire in the harness as it enters the bulkhead connector. As you can see, the red wire is showing some copper where it goes into the connector, indicating all is not right there.


2. I cut the red wire close to but not flush with where it enters the connector. This to give me enough wire to splice in the bypass, and leaving enough that I can insulate the old wire at the connector.


3. I spliced the bypass wire (10 GA ) to the red wire coming from the horn relay, using a connector with the plastic insulation removed. I used black wire for the bypass to make it less obvious. The red wire coming from the horn relay is protected by a fusible link ('67 cars only).


4. I slipped on a piece of shrink tubing to insulate the splice connector, later using a blow dryer to shrink the tubing.
I

5. Luckily, there was an unused firewall grommet right next to the bulkhead connector, so I ran my bypass wire through that into the cabin. In this photo you can see the bypass wire entering the cabin, to the right of the round silver flasher and beneath the hood release cable.
Lu

6. Here is the spliced bypass wire threaded under the inboard connector wire bundle on its way to the gommet on the firewall. I insulated the orphaned red wire stub at the bulkhead connector, just in case.


7 Inside the car, just above the driver's side kick panel, is the headlight motor circuit breaker. I'll connect the bypass wire to the shorter right side stud labelled "BAT" on the circuit breaker.


8. Here I've connected the bypass wire to the circuit breaker after splicing a ring terminal onto the wire.


10. Here's the finished installation under the hood. I rewrapped all exposed wiring using Scotch "33" electrical tape. The bypass wire isn't too obvious, especially once the hood latch assembly is back in place.


I removed the two screws attaching the fusebox to the firewall (inside the cabin) to inspect its condition. All connections were tight, and clean, confirming my problem was located at the bulkhead connector, not at the fuse box.


The repair is a success. The car runs and operates normally. If I wiggle the bulkhead connector the power to the cabin stays on. Before I could interrupt power to the cabin by wiggling this connector.

My only remaining question is: Did I connect the bypass wire to the proper circuit breaker? My car has factory power windows. These are protected by an identical looking circuit breaker, mounted also on the driver's side kick panel. On my car there are two such brekers, one above the other. I connected my bypass wire to the lower breaker, and everything works just fine. But, have I connected my bypass wire to the headlight motor CB, or the power window CB?

On my car the power windows operate with the key out of the ignition. I read that in '67 the power windows are supposed to work only with the key in the ignition. A previous owner must have wired the windows so they would operate without the key in the ignition. That aside, how do I confirm which circuit breaker is which? Lastly, does it matter if the bypass wire is connected to the headlight motor CB, or the power window CB? Both have a hot terminal, so would be equivalent as a connection point for the bypass wire, correct?
Thanks again to all who helped me with this project!

Alex

 

I can't confirm that you're tied into the circuit breaker for the headlight motors, but you can easily determine that by disconnecting the wire from the other side of it and see whether it's the HL motors or the PW motors that no longer operate.

Live well,

SJW

 

Thanks Fufu, that is a very well done wiring explanation, my 67 is a power window car, I'll do exactly what you did. I also would like my windows to operate with key out, older GM cars were that way.

 

it doesn’t matter, both circuit breakers are connected to the same source. Both the power windows and the headlight rollovers work with or without the key on it doesn’t matter.
Physically, connecting to the batt side of the headlight rollover c/b is closer to factory wiring and eliminates the short red wire from one side of the fuse box to the other where the power windows plug on. The difference would be if you unplugged the red wire on the fuse box connector (marked p/w) lug you would remove power from the cabin if you use the p/w breaker. If you connect it to the headlight rollover breaker, removing that p/w window red wire at the fuse box would only remove power to the power windows and cabin power would remain on.

 

Thanks 65GSvert for the info on how to determine which circuit breaker I connected my bypass wire to.

When looking at my fusebox, I see two plugs connected to the lowest set of jack spots that are labelled "POWER WINDOWS" See photo below.

Two orange wires emerge from the left jack, with one short wire ending in a terminal that is connected to nothing. A red wire lis connected to the right side jack, this presumably going to the power window circuit breaker. Do you have any idea what that 2nd orange wire with un-used connector is for? Is this factory, or something added by Bubba (previous owner)?. What use would this have?

The power windows on my car operate with the key out. I read that GM changed the wiring for 1967 so that the key had to be in the ignition (ACC or RUN position) for the power windows to work. I wonder if this was a mid-year change, or if my car was modiffied so the windows would operate without the key?

 

 

It's been a while sold my 63 corvettes 4 years ago,
My friend has a problem with the clock.
He found fuse on bottom of fuse box bad he put 20 amp in, and the clock worked next day. it blew again
He emailed me he put a 30 amp in I told him to take it out,
could catch on fire

I don't have any diagrams have all the diagrams deleted after selling the Corvette,
any way this is what I have
from him,

See the splices after wires got loose and got cut from alternator,
He spliced them back that looks good to me Notice the red wire I think that's a tap for new circuits,
From memory the orange circuit feeds the glove box and coruesty lites and the clock ,
Theres a ground touching just enought to blow the 20 amp
been out of this fourm for 4 years but rembemer you were pretty good at figuring out this stuff ,
Sold the 63 for 93 000 and moved on did my pickup a 57 truck just sold it for 46000 on bring a trailer ,Great way to move nice cars Check my grage out rtruman.com
any help would get my brain going angain Thanks Richard Truman