Led reverse light swap.

[Nigel Blandin]

Brain fart No 32.

so, old Seven, 1990.

single pole reverse switch, which acts as the earth.

the reverse light has an ign switched live and this earth from the gearbox.

with a traditional reverse light, no problem.

At the end  of the loom you have green( ign switched live) and green/purple ( rev light switch)

but, the new Caterham combined number plate and reverse light led only has 3 wires, red( no plate) green ( rev) and black earth. 
 

how do I get a feed to the light when the unit has a common earth? As it is an led that changes "form" depending on the feed in, I don't see how.

 

[Jonathan Kay]

There's a thread describing the various options... change the switch, add a relay, modify the earth wiring in the new lamp unit... I'll have a look...

... found it: Reverse light & New Caterham Light Kit.

Jonathan

[Nigel Blandin]

Thanks Jonathan,

Thanks for that. I think the common earth on the new led No plate and reverse light unit was the problem.

Whichever way I go, new switch or relay I have to get some bits. Boy, it"'ll be much easier when I am living on the mainland- there is nothing here in the way of motor factors any more.  
 

 

 

[Sooty]

Nigel, have you checked the wiring, normally on a car that age, mine is 1989, the reverse light is operated via a permanent live and a switched earth at the gearbox switch

[rkeywood]

Hi Nigel, check the wire colours. As you say the live to the reversing lights is green but the switched earth should be green/brown. The live for the brake lights from the brake switch should be green/purple

 

[Nigel Blandin]

Yup, that was my typo! Ihave it sussed now.

I am replacing the switch with a twin pole and have picked up the switched green to feed that.

then I am using the green/brown to feed the light. All works now.....

But! I came back to it tonigh5 and all the rhs was dim. I checked and rechecked, removed everything, checked the volts, the arms, the continuity...2 hours later I checked the earth by quickly adding another and bingo!

As my old electrical gu6 used to say " Check the earth first, not last boy" Doh!