Transmission reverse switch?

Gotta love that wiring . . .
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Nanonevol
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Your car is a: 1977 Fiat 124 Spider
Location: Medway, Massachusetts

Transmission reverse switch?

Postby Nanonevol » Thu Jul 06, 2017 12:30 pm

Tried to get my state inspection sticker and found I had no backup lights. Took her home and found the bulbs and connectors good so it was something in the wiring or the switch. Looking under my wood panel at the stick shift I found a connector coming up from the transmission and using my meter found that two terminals on the connnector would connect when I put it in reverse. Problem is that they connect in any gear! Do I have the wrong connector or is it a problem in the switch at the transmission? Spider is a '77. I did the rebuild on the transmission last year and it's possible I did something wrong there. Any advice?
The wires coming from this connector are two blue and white on one side and white on the other.
1977 Fiat Spider
1985 Jaguar XJ6
1967 Triumph Bonneville (hard-tail chopper)
1966 BSA Lightning

kmoses
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Your car is a: 1979 Spider 2000

Re: Transmission reverse switch?

Postby kmoses » Thu Jul 06, 2017 1:07 pm

The backup light switch shaft may be stuck in (ON) and not extending back to the out (OFF) position. The only way to check is to pull the switch. Also the connector to the back up lights can be jumpered to make sure the circut works from the connector back.

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Nanonevol
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Re: Transmission reverse switch?

Postby Nanonevol » Thu Jul 06, 2017 2:43 pm

Thanks, that's a reasonable hypothesis, however, I read a few posts here and then crawled under the car (groan)and found my reverse switch hooked up to nothing - just clipped wires doing nothing. No idea how long it's been like that - I don't think about my backup lights much. The inspection station does though so I'll head back there for the 3rd time. They must be getting sick of me :)
1977 Fiat Spider
1985 Jaguar XJ6
1967 Triumph Bonneville (hard-tail chopper)
1966 BSA Lightning

spider2081
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Re: Transmission reverse switch?

Postby spider2081 » Fri Jul 07, 2017 6:37 pm

The wires coming from this connector are two blue and white on one side and white on the other


This is the cars side of the connector. The Blue/white wire is power from the fuse. The white wire connects to the back up light bulbs. The back up switch should have 2 black wire coming from it that should be in a 2 pin mating connector for the Blue/white , white wire connector.

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Nanonevol
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Your car is a: 1977 Fiat 124 Spider
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Re: Transmission reverse switch?

Postby Nanonevol » Fri Jul 07, 2017 7:55 pm

Thanks. I looked pretty foolish going back to the inspection station with back up lights in all gears after being sent away once with no back up lights at all. I think I need to throw the guy a tip - he could have slapped an "R" for reject sticker on and made me pay again.
I imagine that other transmission connection is an emissions feature that I won't miss.
1977 Fiat Spider
1985 Jaguar XJ6
1967 Triumph Bonneville (hard-tail chopper)
1966 BSA Lightning

zachmac
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Your car is a: 1978 Spider [1979 2 ltr engine]
Location: Aiken, SC

Re: Transmission reverse switch?

Postby zachmac » Sat Jul 08, 2017 12:44 pm

Nanonevol wrote:Thanks. I looked pretty foolish going back to the inspection station with back up lights in all gears after being sent away once with no back up lights at all. I think I need to throw the guy a tip - he could have slapped an "R" for reject sticker on and made me pay again.
I imagine that other transmission connection is an emissions feature that I won't miss.


I think maybe the other connector is a neutral safety switch to keep you from cranking while in gear but I could be wrong? Seem to remember seeing one in some circuit? On the other hand that could be the disconnected switch on my clutch pedal?
Jeff Klein, Aiken, SC
1980 FI Spider, Veridian with Tan (sold about a year ago), in the market for another project
1989 Spider, sold
2008 Mercedes SL65
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baltobernie
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Re: Transmission reverse switch?

Postby baltobernie » Sat Jul 08, 2017 8:46 pm

zachmac wrote:I think maybe the other connector is a neutral safety switch to keep you from cranking while in gear but I could be wrong? Seem to remember seeing one in some circuit? On the other hand that could be the disconnected switch on my clutch pedal?
These cars do not have a neutral safety switch from the factory. Both the clutch button switch and the not-reverse-gear switch are emissions switches. Both are used in various circumstances to keep the carb from closing abruptly and spiking emissions.

zachmac
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Re: Transmission reverse switch?

Postby zachmac » Sun Jul 09, 2017 8:30 am

baltobernie wrote:
zachmac wrote:I think maybe the other connector is a neutral safety switch to keep you from cranking while in gear but I could be wrong? Seem to remember seeing one in some circuit? On the other hand that could be the disconnected switch on my clutch pedal?
These cars do not have a neutral safety switch from the factory. Both the clutch button switch and the not-reverse-gear switch are emissions switches. Both are used in various circumstances to keep the carb from closing abruptly and spiking emissions.


Re-examining the wiring diagrams Baltobernie is of course correct. Two functions from tranny switches: back up light actuation and emissions control input.
Jeff Klein, Aiken, SC
1980 FI Spider, Veridian with Tan (sold about a year ago), in the market for another project
1989 Spider, sold
2008 Mercedes SL65
2008 S600 Mercedes V12

DrivesLikeFoust
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Your car is a: 1981 Fiat 2000 Spider

Re: Transmission reverse switch?

Postby DrivesLikeFoust » Wed Aug 02, 2017 9:29 pm

Hello. I drive an '81 Spider and have found that my reverse wires coming from the transmission switch have been chewed or torn apart (hope it didn't involve the driveshaft) and as a result I also have no reverse lights. The wires are missing. I have pulled out the center console and saw no sign of them. Not sure exactly what to look for. Any suggestions?

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Nanonevol
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Your car is a: 1977 Fiat 124 Spider
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Re: Transmission reverse switch?

Postby Nanonevol » Thu Aug 03, 2017 8:45 am

There should be a white plastic probably 2 pin connector somewhere near the lower console. Check the wiring diagrams for wire color. It's a very simple circuit. Auroricambri sells the switch. Wires on my switch were torn up as well. Could they have gotten caught up in the driveshaft somehow?
1977 Fiat Spider
1985 Jaguar XJ6
1967 Triumph Bonneville (hard-tail chopper)
1966 BSA Lightning

DrivesLikeFoust
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Your car is a: 1981 Fiat 2000 Spider

Re: Transmission reverse switch?

Postby DrivesLikeFoust » Thu Aug 03, 2017 11:31 pm

Okay thanks. I'll dig back into it. When I got the car the wires were torn. I imagine there was too much slack and it did get caught in the propshaft.

maxdog
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Re: Transmission reverse switch?

Postby maxdog » Sun Sep 03, 2017 11:04 pm

Hi
My 1979 124 S has " logical " reverse lights . They only work when the lights are on ! I suppose the logic is :
Lights are needed when it's dark
In day light you can see what you are about to reverse into , so you don't need reverse lights .
You only need reverse lights to see what you are going to hit when it's dark .
When it's dark you will have your lights on , so it's logical to wire the reverse lights with all the other lights ??
I think this is called " fuzzy logic " It makes some sort of loopy sense
Of course FIat may just have wired it incorrectly in 1979 ,in old British car terms a Friday afternoon special ??
Maxdog

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Nanonevol
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Your car is a: 1977 Fiat 124 Spider
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Re: Transmission reverse switch?

Postby Nanonevol » Mon Sep 04, 2017 8:42 am

You might check the law on that locally. I think most places the reverse lights must come on whether or not the headlights are on.
1977 Fiat Spider
1985 Jaguar XJ6
1967 Triumph Bonneville (hard-tail chopper)
1966 BSA Lightning


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