Backup Switch Wiring

[Murray]

Spent some time with the wiring schematic to understand the backup
switch. This is primarily for '68 cuda 4-sp. but may apply to other "A" bodies. The switch itself is two-prong as seen in the photo. One wire is hot. Both wires are violet and are included with the wiper motor wire loom that is a separate plug- in at the bulkhead connecter. On the other side of the connecter under the dash, one of the violet wires changes to white and goes up to the radio connecter where it splices into the red wire. This is where this circuit gets it's juice for the backup lites. The remaining violet wire travels thru the loom to the body wire loom connecter behind the left kick pad and out to the backup lites, now a single violet wire. So the backup switch creates an open circuit, and when you put it in reverse, the switch connects the two lugs and you have backup lites. Cars with 4-sp do not have a neutral safety switch, which is why the starter relay on these cars has one of the terminals soldered to ground as shown in the pic.

 

[67Dart273]

I missed something somewhere......is there a question here?

The automatics up through 68 the backup switch is on the column or console shifter. Doesn't go through the bulkhead like the 4 speed cars do. I have no idea how the 3 speeds stick switches work, never worked on one.

 

[genecoppersmith]

Spent some time with the wiring schematic to understand the backup
switch. This is primarily for '68 cuda 4-sp. but may apply to other "A" bodies. The switch itself is two-prong as seen in the photo. One wire is hot. Both wires are violet and are included with the wiper motor wire loom that is a separate plug- in at the bulkhead connecter. On the other side of the connecter under the dash, one of the violet wires changes to white and goes up to the radio connecter where it splices into the red wire. This is where this circuit gets it's juice for the backup lites. The remaining violet wire travels thru the loom to the body wire loom connecter behind the left kick pad and out to the backup lites, now a single violet wire. So the backup switch creates an open circuit, and when you put it in reverse, the switch connects the two lugs and you have backup lites. Cars with 4-sp do not have a neutral safety switch, which is why the starter relay on these cars has one of the terminals soldered to ground as shown in the pic.View attachment 1715161400View attachment 1715161401View attachment 1715161403View attachment 1715161404View attachment 1715161401 View attachment 1715161401 View attachment 1715161401 View attachment 1715161403 View attachment 1715161404 View attachment 1715161400 View attachment 1715161401 View attachment 1715161403 View attachment 1715161404

Murray: Thanks a lot for the information, once again that's what I needed and it's greatly appreciated. I had most of it figured out except for where you stated that
"one of the violet wires changes to white and goes up to the radio connecter where it splices into the red wire." I'll find that connection and then should be good to go.

 

[famous bob]

Murray: Thanks a lot for the information, once again that's what I needed and it's greatly appreciated. I had most of it figured out except for where you stated that
"one of the violet wires changes to white and goes up to the radio connecter where it splices into the red wire." I'll find that connection and then should be good to go.

My 68 fastback`s orig type tail lenses are in pretty good shape, but the back up lights aren`t bright enough to worry about. I had a switched wire laying in the trunk from a total rewire and hooked it up to mt b/u plights, just the he-- of it, "not worth the effort !"

 

[RedFish]

Radio and reverse. Lets put those Rs together on the same fuse. I like it
My memory sux but I think I recall reading that earlier models picked up the switched fused 12 volts for reverse lamps and/or other off the wiper switch connector,, Adding complication to the crowd of wires already there. Regardless... factory wiring diagrams tell all.

 

[genecoppersmith]

Radio and reverse. Lets put those Rs together on the same fuse. I like it
My memory sux but I think I recall reading that earlier models picked up the switched fused 12 volts for reverse lamps and/or other off the wiper switch connector,, Adding complication to the crowd of wires already there. Regardless... factory wiring diagrams tell all.

Redfish: I'm an old MOPAR guy, but a relatively new FABO guy so I'll ask you to bear with me as I learn the protocol. I'm converting my 68 fastback from a 904 console to an 833 and retaining the console. Murray was helping me address the backup light wiring. I'm trying my best to do this the same way mother MOPAR did it so the photos and text from Murrays original 4 speed car are invaluable. I have the FSM, my Fluke DMM and plenty of time. Now all I need to do is find the correct red wire. Thanks for the help, Gene

 

[RedFish]

They aren't all the same. Far from it actually. So did your 68 have the reverse lamp switch mounted on the floor shifter or on the transmission? If it was on the floor mounted shifter, there is another connector at lower end of steering column where a column mounted reverse lamp which could have been. In this case the console harness is a add on extension.
Your radio has 2 connectors. One of those has a red tuner power wire and a orange dial illumination wire. How the factory harness for a manual trans build tied into this red wire? I don't know. In some cases they used a special little tap harness with connectors to go in between 2 standard connectors. The trunk lamp harness is another example. ( This would explain the short length of white wire described above ). Anyway...
Short of buying the alternate under dash harness, You'll need to cut and splice or use a wire tap to get 12 volts from the red radio power wire.
If it were me... I would follow the console harness back into the cars harness. There is or was a hot purple wire there somewhere. Your hot purple wire may have originated in the fuse box. If you don't utilize it, it's just floating about somewhere, so you still don't have exactly like ma mopar did it.

 

[genecoppersmith]

They aren't all the same. Far from it actually. So did your 68 have the reverse lamp switch mounted on the floor shifter or on the transmission? If it was on the floor mounted shifter, there is another connector at lower end of steering column where a column mounted reverse lamp which could have been. In this case the console harness is a add on extension.
Your radio has 2 connectors. One of those has a red tuner power wire and a orange dial illumination wire. How the factory harness for a manual trans build tied into this red wire? I don't know. In some cases they used a special little tap harness with connectors to go in between 2 standard connectors. The trunk lamp harness is another example. ( This would explain the short length of white wire described above ). Anyway...
Short of buying the alternate under dash harness, You'll need to cut and splice or use a wire tap to get 12 volts from the red radio power wire.
If it were me... I would follow the console harness back into the cars harness. There is or was a hot purple wire there somewhere. Your hot purple wire may have originated in the fuse box. If you don't utilize it, it's just floating about somewhere, so you still don't have exactly like ma mopar did it.

Here's what I found: My reverse lamp switch was mounted on the floor shifter. Four wires went to the passenger kick panel area. Violet and white followed the lower dash ledge to the steering column, then to the vicinity of the bulkhead connector, where they plugged into two more white and violet wires that disappeared into the dash wiring harness. White was the powered wire and joined the red radio wire at the radio connecter. Violet travels to the drivers kickpanel area to another coupler and then back to the reverse lights. I purchased a manual trans back up light harness from YO. They had 2 different harnesses, something like 67 and older, and 69 and newer. I couldn't find a 68 specific harness. It came as an M&H product and is obviously designed to terminate at the engine compartment side, in the C and D cavity of the bulkhead connector. I'm now convinced that I have what I need, it should simply plug in. Thanks for the help and information. Greatly appreciated.

 

[RedFish]

The reverse lamp switch for automatic, on the column or extended to the floor shifter moved to the transmission during 68 model production. Since the switch always was on the manual trans, the move made the in car harnesses more similar ( reverse lamp wiring routed through bulkhead for all ). earlier were different inside and out. Anyway... This may explain the aftermarkets' inability to list what is exactly correct for a 68 build. Reads like you have it fingered out.

 

[Murray]

Redfish, thanks for the clarification. Funny how some things can change within a model year.