Electrics: 70: Reversing lights, all LED only cars

[ian.stone]

Just bought a 2020 S60 to replace a 5 year old V60.

I live on a single track road with no designated passing places.

First night out in the dark I had to reverse for an oncoming vehicle as I was only 20 meters from a field gate. I naively thought the reversing warning lights would give enough light to enable the rear camera to work. Wrong no light out back and no moon to help. Hazard warning lights did help but not enough light to enable me to reverse safely into the gateway. All my previous cars 140, 740, 850, V70 and V60 had incandescent reversing warning light bulbs which I swapped out for higher output bulbs. The CAN bus friendly LED ones on the market are superb. Problem with this newer car is the reversing warning light are LED.

Does anyone have a solution?
Some problems I can see fitting external lamps:

Aesthetics; fit flush reversing lights on the rear bumper, problem, there is no flat surfaces big enough.

Power: yet to be investigated. I have not looked but guess the rear light modules have a CAN bus input and power so tapping the feed to the reversing warning light is not possible. The user manual does not list a fuse that I can see which relates to the light module.

[Drunk]

I haven't done a volvo in a long time, but my first thought would be a simple relay solution. Use the signal for the reversing lights to power a relay and tap the main power from like a cigarette lighter socket in the back to power the added rear lights. If you have a towing hitch, you could probably make some kind of bracket to hold the light.

[Father Ted]

Originally Posted by Drunk

I haven't done a volvo in a long time, but my first thought would be a simple relay solution. Use the signal for the reversing lights to power a relay and tap the main power from like a cigarette lighter socket in the back to power the added rear lights. If you have a towing hitch, you could probably make some kind of bracket to hold the light.

I'd use a relay too. A transistorised relay wouldn't (shouldn't?) cause any error messages with CAN bus.
https://www.ebay.co.uk/itm/12V-Trans...IAAOSwLahau6CA

But, to pick up the ball Drunk dropped.....If you have a towbar, the towing electrics will have a "normal" 12v output for a reversing lamp.

[ian.stone]

As I said can't get to the reverse warning light. Its LED's which are in one big moulded unit with other lights. There is a tow hitch connector which plugs into a module which will need to be purchased and programmed in. Costs a fortune, not an option. I know there are also problems with fooling the car it has a trailer connected.

There are devices that give CAN bus to relay output but you have to no the "reverse gear selected" code to drive them. That means using a sniffer as Volvo are not going to hand this information over. In the old days the solution was easy, swap out the bulbs.

[Drunk]

Originally Posted by ian.stone

As I said can't get to the reverse warning light. Its LED's which are in one big moulded unit with other lights. There is a tow hitch connector which plugs into a module which will need to be purchased and programmed in. Costs a fortune, not an option. I know there are also problems with fooling the car it has a trailer connected.

There are devices that give CAN bus to relay output but you have to no the "reverse gear selected" code to drive them. That means using a sniffer as Volvo are not going to hand this information over. In the old days the solution was easy, swap out the bulbs.

You don't need the light, just the cable for it. The power source for the rear lights is gonna be a simple cable in the connector of the back of the rear headlight. Check the voltage with a multimeter but i'm 95% sure it's gonna be 12V since these new led headlights usually reduce the voltage inside the light itself.