Towing reverse light/12s socket

terranosaurusdoug · 21-03-2016, 16:11

Hi all, does anyone know how many volts I should have at the reverse light pin on my 12s socket on my 2000 2.7?
I'm trying to find why reverse light on caravan is not working, tested 12s and I'm getting 12.9/13v at reverse lamp pin, I'm guessing that is right, thanks, Mark.

jims-terrano · 21-03-2016, 17:24

Should get the same voltage at the car revs lamp and the pin on the socket. I could understand if there was a drop at the rear of the caravan but not a great deal if any.
Trace and check the cables from your socket to the vehicle wiring. I've seen it on terranos where the fitter has scotch locked or twisted direct into vehicle wiring behind the bumper where it is open to the elements instead of connecting to the wiring inside the boot area.

micktheshed · 21-03-2016, 17:25

Anything over 12V should be OK. Even given a good battery (@12.5V+) there will be some drop along the way. I was told, many years ago, that 1/4V+ drop per connection should be expected so keep these to a min.
Also don't use solder on compression joints (such as the plug & skt have) use metal pinch rings if at all possible, or nothing at all. Solder tends to extrude over time & can result in a loose, or poor, electrical connection. On items such as these I also dip the wire ends in copper grease to stop them corroding.

A good tip is to make sure all the pins are gripping each other by spreading their slots slightly with a fine blade then spray with general purpose silicon. DON'T use WD40 as this can cause the plastic housing to deteriorate. Ideally the plug should be a 'drag' fit into the socket.

The quality of the earth connection cannot be over-rated especially the earth pin(s) themselves. I always run one earth wire to the bodywork & another (of 2.5m2) direct to the battery. These wires are also connected to each other. I also use 2 scotch-locks rather than one as they have a less than 100% success rate and can get worse over time.

Overkill? maybe, but it's worth it for better reliability as these plug/skt combinations can cause weird problems elsewhere.

terranosaurusdoug · 21-03-2016, 21:56

Hi jim, yeah I am less than impressed with some of the joints ive seen, going to trace a mystery wire tomorrow too!

Mick, thanks for the tips mate, didnt know that bout wd40 either!!
I'm going the check the caravan wiring for reverse tomorrow so l'll give the earths some attention!

jims-terrano · 21-03-2016, 22:11

If memory serves it's yellow for reverse lights and white for the earth in the 12s connections.

terranosaurusdoug · 21-03-2016, 22:19

Quote:

Originally Posted by jims-terrano

If memory serves it's yellow for reverse lights and white for the earth in the 12s connections.

I think thats right, there is a good post on here somewhere, 12s has two earths, one is just for fridge.

terranosaurusdoug · 23-03-2016, 22:58

Got it sorted, didnt have to go too deep, traced power from the truck to some fuses at front of van then nowt, fuse was ok when I pulled it out to see, put it back in, thought I might as well change it to make sure, when I pulled it out again it fell to pieces, new fuse in and hey presto, it works

Bloody cheap fuse I suppose, what brand do you guys use, any recommendations of where or what to buy!, Mark.

21-03-2016, 16:11	#1
terranosaurusdoug Senior Member Join Date: Sep 2014 Location: Yorkshire, J33 M62 Vehicle: 2000 Terrano lwb 2.7TDI Posts: 5,500	Towing reverse light/12s socket Hi all, does anyone know how many volts I should have at the reverse light pin on my 12s socket on my 2000 2.7? I'm trying to find why reverse light on caravan is not working, tested 12s and I'm getting 12.9/13v at reverse lamp pin, I'm guessing that is right, thanks, Mark.

21-03-2016, 17:24	#2
jims-terrano Senior Member Join Date: Sep 2004 Location: UK Posts: 12,965	Should get the same voltage at the car revs lamp and the pin on the socket. I could understand if there was a drop at the rear of the caravan but not a great deal if any. Trace and check the cables from your socket to the vehicle wiring. I've seen it on terranos where the fitter has scotch locked or twisted direct into vehicle wiring behind the bumper where it is open to the elements instead of connecting to the wiring inside the boot area.

21-03-2016, 17:25	#3
micktheshed Senior Member Join Date: Feb 2011 Location: warwickshire Vehicle: Dec 2004, terrano 3l Auto Posts: 313	Anything over 12V should be OK. Even given a good battery (@12.5V+) there will be some drop along the way. I was told, many years ago, that 1/4V+ drop per connection should be expected so keep these to a min. Also don't use solder on compression joints (such as the plug & skt have) use metal pinch rings if at all possible, or nothing at all. Solder tends to extrude over time & can result in a loose, or poor, electrical connection. On items such as these I also dip the wire ends in copper grease to stop them corroding. A good tip is to make sure all the pins are gripping each other by spreading their slots slightly with a fine blade then spray with general purpose silicon. DON'T use WD40 as this can cause the plastic housing to deteriorate. Ideally the plug should be a 'drag' fit into the socket. The quality of the earth connection cannot be over-rated especially the earth pin(s) themselves. I always run one earth wire to the bodywork & another (of 2.5m2) direct to the battery. These wires are also connected to each other. I also use 2 scotch-locks rather than one as they have a less than 100% success rate and can get worse over time. Overkill? maybe, but it's worth it for better reliability as these plug/skt combinations can cause weird problems elsewhere.

21-03-2016, 21:56	#4
terranosaurusdoug Senior Member Join Date: Sep 2014 Location: Yorkshire, J33 M62 Vehicle: 2000 Terrano lwb 2.7TDI Posts: 5,500	Hi jim, yeah I am less than impressed with some of the joints ive seen, going to trace a mystery wire tomorrow too! Mick, thanks for the tips mate, didnt know that bout wd40 either!! I'm going the check the caravan wiring for reverse tomorrow so l'll give the earths some attention!

21-03-2016, 22:11	#5
jims-terrano Senior Member Join Date: Sep 2004 Location: UK Posts: 12,965	If memory serves it's yellow for reverse lights and white for the earth in the 12s connections.

23-03-2016, 22:58	#7
terranosaurusdoug Senior Member Join Date: Sep 2014 Location: Yorkshire, J33 M62 Vehicle: 2000 Terrano lwb 2.7TDI Posts: 5,500	Got it sorted, didnt have to go too deep, traced power from the truck to some fuses at front of van then nowt, fuse was ok when I pulled it out to see, put it back in, thought I might as well change it to make sure, when I pulled it out again it fell to pieces, new fuse in and hey presto, it works Bloody cheap fuse I suppose, what brand do you guys use, any recommendations of where or what to buy!, Mark.