reverse light switch

CLIVERALLY · Sep 1st, 2014, 19:09

After grubbing about I have found the location on the top of the gearbox under a removable plate.

BUT I seem to have two ? -- neither connected - sitting on the drivers seat I guess that the one that is supposed to operate is on the left?

The second switch is probably

there because a bung has been removed and lost ?

so chaps and chapessess give me a bit of info please

Oh Yes, neither is the OD at the end of the box

JP 1800 · Sep 1st, 2014, 21:55

One switch is for the reverse light and the second is for fourth gear for the overdrive. From memory the switch on the right is for the reverse light.

Derek UK · Sep 1st, 2014, 22:32

On the early 1800 remote change there are two switch positions at the front of the gearbox top plate side by side. If there is only one switch fitted, with a blanking plug in the other it will be for the overdrive lockout and that will be in the position that's furthest away from you as you sit in the driver's seat RHD. If there are two, the one nearest you will be for the reversing lights.
The reversing lights can also be switched via simple switch under the alloy cover at the rear of the gearbox. This is usual on the M40 box with no OD. This is actuated by one of the rods that come out of the back of the box when you put it into reverse.

CLIVERALLY · Sep 2nd, 2014, 18:26

Hi

Big thanks - it was the one on the right- and it works!!! my overdrive solenoid seems to be on the end of the box so the second switch I suppose is redundant- the overdrive works fine so I suppose the old adage is if it aint broke - just wondered what it is for

Derek UK · Sep 4th, 2014, 00:28

Not sure which thread to post on but wasn't convinced about the result of the this one so thought it best to add it here.
Picture shows 4 different gearbox tops. Amazon plain M40 top, Amazon M41 with overdrive switch, P1800 remote with overdrive switch and blanking plug, P1800 remote with overdrive switch and reversing light switch.

Notes: The three lids that have an OD switch, all have it fitted in the same position relative to the gearbox top. This one cannot be used for the reversing lights. The plain M40 box doesn't show a reverse switch alloy cover as it has been removed. The Amazon M41 has the reverse switch showing and has the connection for the wire at the top. The 1800 remote with OD switch and blanking plug actually came out of a Ruddspeed Amazon and as it was an add-on to the standard M41, retained the reverse switch position as per the previous picture. The 1800 remote with both switches is from an 1800, I have the complete box/OD/bell-housing. When this remote is fitted it fits near flush to the top of the alloy switch cover but as the terminal for the wire sticks out of the top it's changed in the 1800 to a switch in the top of the remote opposite to the OD one. As noted, with the Ruddspeed Amazon addition it will work with the switch in the rear position but is difficult to access. Not a problem for Rudds as they just chopped a large piece out of the tunnel to fit the remote and then replaced it with a bit of tin sheet held down by self tapping screws. Crude but effective in the short term.
The switches work via a plunger from underneath. When in top gear only, the OD plunger is pushed up and completes the connection inside the switch. Nothing happens until you use the OD switch in the car to provide power to the OD solenoid. If in OD you change down to third the plunger drops and you drop out of overdrive. If you don't touch the inside OD switch, when you change back to top you'll actually go back into OD top. Very annoying when it doesn't want to accelerate. (for a cure for this see Ron's link)
With the reverse switch there is power to the outside terminals when the ignition is on. When you select reverse, the plunger is pushed up inside to complete the circuit.
Apologies for the scruffy state of the Amazon box tops............

CLIVERALLY · Sep 4th, 2014, 20:09

Derek -thanks - mine was the 4th piccie with twin switches. Found a horror story as I unpicked the problem--

The lead to the solenoid from the relay - was direct and made of 3 sections !! joined with lucar spade connectors none were insulated so were sparking merrily on the tranny tunnel!!!!

So getting my trusty wiring diagram- and the wealth of advice from this forum I set about and re wired -- it now works as Sven or whoever intended

Sep 1st, 2014, 19:09	#1
CLIVERALLY Master Member Last Online: May 11th, 2024 18:34 Join Date: May 2010 Location: wetherby	reverse light switch After grubbing about I have found the location on the top of the gearbox under a removable plate. BUT I seem to have two ? -- neither connected - sitting on the drivers seat I guess that the one that is supposed to operate is on the left? The second switch is probably there because a bung has been removed and lost ? so chaps and chapessess give me a bit of info please Oh Yes, neither is the OD at the end of the box

Sep 1st, 2014, 21:55	#2
JP 1800 Master Member Last Online: May 5th, 2024 08:41 Join Date: Aug 2009 Location: Dublin	One switch is for the reverse light and the second is for fourth gear for the overdrive. From memory the switch on the right is for the reverse light.

Sep 1st, 2014, 22:32	#3
Derek UK VOC Member Last Online: Yesterday 12:30 Join Date: Jul 2006 Location: Chatham	On the early 1800 remote change there are two switch positions at the front of the gearbox top plate side by side. If there is only one switch fitted, with a blanking plug in the other it will be for the overdrive lockout and that will be in the position that's furthest away from you as you sit in the driver's seat RHD. If there are two, the one nearest you will be for the reversing lights. The reversing lights can also be switched via simple switch under the alloy cover at the rear of the gearbox. This is usual on the M40 box with no OD. This is actuated by one of the rods that come out of the back of the box when you put it into reverse.

Sep 2nd, 2014, 18:26	#4
CLIVERALLY Master Member Last Online: May 11th, 2024 18:34 Join Date: May 2010 Location: wetherby	Hi Big thanks - it was the one on the right- and it works!!! my overdrive solenoid seems to be on the end of the box so the second switch I suppose is redundant- the overdrive works fine so I suppose the old adage is if it aint broke - just wondered what it is for

Sep 4th, 2014, 00:28	#5
Derek UK VOC Member Last Online: Yesterday 12:30 Join Date: Jul 2006 Location: Chatham	Not sure which thread to post on but wasn't convinced about the result of the this one so thought it best to add it here. Picture shows 4 different gearbox tops. Amazon plain M40 top, Amazon M41 with overdrive switch, P1800 remote with overdrive switch and blanking plug, P1800 remote with overdrive switch and reversing light switch. Notes: The three lids that have an OD switch, all have it fitted in the same position relative to the gearbox top. This one cannot be used for the reversing lights. The plain M40 box doesn't show a reverse switch alloy cover as it has been removed. The Amazon M41 has the reverse switch showing and has the connection for the wire at the top. The 1800 remote with OD switch and blanking plug actually came out of a Ruddspeed Amazon and as it was an add-on to the standard M41, retained the reverse switch position as per the previous picture. The 1800 remote with both switches is from an 1800, I have the complete box/OD/bell-housing. When this remote is fitted it fits near flush to the top of the alloy switch cover but as the terminal for the wire sticks out of the top it's changed in the 1800 to a switch in the top of the remote opposite to the OD one. As noted, with the Ruddspeed Amazon addition it will work with the switch in the rear position but is difficult to access. Not a problem for Rudds as they just chopped a large piece out of the tunnel to fit the remote and then replaced it with a bit of tin sheet held down by self tapping screws. Crude but effective in the short term. The switches work via a plunger from underneath. When in top gear only, the OD plunger is pushed up and completes the connection inside the switch. Nothing happens until you use the OD switch in the car to provide power to the OD solenoid. If in OD you change down to third the plunger drops and you drop out of overdrive. If you don't touch the inside OD switch, when you change back to top you'll actually go back into OD top. Very annoying when it doesn't want to accelerate. (for a cure for this see Ron's link) With the reverse switch there is power to the outside terminals when the ignition is on. When you select reverse, the plunger is pushed up inside to complete the circuit. Apologies for the scruffy state of the Amazon box tops............

Sep 4th, 2014, 20:09	#6
CLIVERALLY Master Member Last Online: May 11th, 2024 18:34 Join Date: May 2010 Location: wetherby	Derek -thanks - mine was the 4th piccie with twin switches. Found a horror story as I unpicked the problem-- The lead to the solenoid from the relay - was direct and made of 3 sections !! joined with lucar spade connectors none were insulated so were sparking merrily on the tranny tunnel!!!! So getting my trusty wiring diagram- and the wealth of advice from this forum I set about and re wired -- it now works as Sven or whoever intended

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