Towbar wiring

[bigegg]

As I posted earlier, I've just got hold (finally!) of a towbar for my '99 gs300.

I need to connect up my electrics.

I bought a "black box" relay thing and a generic 12N (7 pin) socket.

 

Does anyone have any advice on where to route the cable into boot, where to mount the relay box, and where to splice into the wiring harness?

or just a wiring diagram/ cable colours for the lights would do.

 

thanks

 

 

 

[Britprius]

23 minutes ago, bigegg said:

As I posted earlier, I've just got hold (finally!) of a towbar for my '99 gs300.

I need to connect up my electrics.

I bought a "black box" relay thing and a generic 12N (7 pin) socket.

 

Does anyone have any advice on where to route the cable into boot, where to mount the relay box, and where to splice into the wiring harness?

or just a wiring diagram/ cable colours for the lights would do.

 

thanks

 

 

 

Can you supply a manufacturer, and part number for the "black box" or even a picture might help. 
Most of the connections can be made behind the rear lights, but depending on your needs you may require a 12 volt feed capable of supplying around 30 amps.

Are you towing a caravan, small trailer, or is it going to be used for a bicycle rack with a lighting board?

John.

[bigegg]

Black box is a "ring" smart logic relay 12n single rct485

Small(ish) trailer - sub 1.5T, maybe a bike rack.

Occasionally a small touring caravan (just a 12n single socket needed).

It does need a larger power supply - fused at 15A

 

 

[Britprius]

I connected all the wiring from behind the rear lights on my GS450H, and I would believe this would also be the best place on your GS300. 
Picking up a 12 volt feed will be more difficult on your car as I believe the Battery is under the bonnet. Feeding a wire through the car is a fiddle to say the leased, and it may be easier to take the wire under the car having picked up a supply "fused" from the Battery.
I found an existing rubber grommet in the rear boot wall to exit wires to behind the rear bumper. The 12 volt feed could come in this way to feed the smart logic relay fitted behind the lights.

If you can make up a small 12 volt test lamp or use a volt meter it is a simple matter to check which wires to use. Turn on the side lights and find which wire has a 12 volt feed turn off the lights, and the feed should disappear. do the same for stop lights, indicators L/R , fogs, and reversing lights.

John.

15 hours ago, bigegg said:

Black box is a "ring" smart logic relay 12n single rct485

Small(ish) trailer - sub 1.5T, maybe a bike rack.

Occasionally a small touring caravan (just a 12n single socket needed).

It does need a larger power supply - fused at 15A

 

 

22 hours ago, bigegg said:

As I posted earlier, I've just got hold (finally!) of a towbar for my '99 gs300.

I need to connect up my electrics.

I bought a "black box" relay thing and a generic 12N (7 pin) socket.

 

Does anyone have any advice on where to route the cable into boot, where to mount the relay box, and where to splice into the wiring harness?

or just a wiring diagram/ cable colours for the lights would do.

 

thanks

 

 

 

Can you supply a manufacturer, and part number for the "black box" or even a picture might help. 
Most of the connections can be made behind the rear lights, but depending on your needs you may require a 12 volt feed capable of supplying around 30 amps.

Are you towing a caravan, small trailer, or is it going to be used for a bicycle rack with a lighting board?

John.

[bigegg]

It took me all day, but it's done!

 

Ran the 7 strand into the boot through the drain grommets in the wheel well, then under the hard plastic trim around the lock to the passenger side wing.

Found the correct wires using a multimeter, then spliced in with wago connectors - now I know it works, I'll splice them properly with solder+heat shrink.

Ran a fused 15a supply from the Battery (under the bonnet) under the car and into the boot through the same grommet - had to use 2.5mm green+yellow mains earth cable because I couldn't find my reel of red 😞

 

ill update this thread with the cable colours later.