Brake Controller wiring

Member - Jeremy W (SA) posted:

Hello Vince,

Thanks for the reply.

Here's the whole story:-

The brake controller has 4 wires:

1. Blue - goes to the brake via the trailer plug - no probs on this
2. White - to earth - no probs on this either.
3. Red goes to the brake switch - Here's the problem.
4. Black goes to +12V = no problem here.

So you get the signal (red wire) from the tail light itself OK. Now I take it that the wire goes to 12V when the brake light goes on (of course, the other side is 0V!!). Right! I guess that this is the same as connecting it to the brake switch.

OK now I understand.

Cheers and Beers,

Jeremy.

Racey posted:

The brake switch of many modern vehicles is connected to the computer and not direct to the stop lights. The lights are then fed via relay. This makes it essential not to direct connect the controller to the stop switch. The Tekonsha instructions do mention some models, Falcon being one.

Cheers

Racey

Member - Jeremy W (SA) posted:

Thanks Racey.

I read the instructions that came with the unit and they made a big point of mentioning Ford models.

Thanks for pointing this out.

This is the good thing about a forum - its the stuff from "left field" that is pointed out. Mercifully I don't have to worry about this one.

I shall add this bit of knowledge to my memory banks (well, bank) !!

Jeremy.

Member - G N (VIC) posted:

Hi all

Just another question on this matter.

what size wire do you need to run to the back of the vehical?

Regards
GN

Member - Jeremy W (SA) posted:

OK Graham,

I'll try that in the morning - yes it sounds neater.

I'm in the process of preparing for a new camper trailer. The vehicle is fairly new (3 months old) so I thought I'd run wires and put in the Anderson plugs. I hate wiring cars (but it has to be done!!) so I thought I'd get it out of the way - quick smart.

Many thanks for the tips,

Rgds,

Jeremy.

BTW.

6mm wires should be more than adequate as a 6M length cable (2 wires) will drop 0.68V at 20A. If the brakes take 20A then they will 90% of the power they would receive with no voltage drop. If the brakes take 10A (0.34V drop) then the brakes receive 95% of the max power.

How about that?

Jeremy.

Member - Jeremy W (SA) posted:

If the brakes take 20A then they will 90% of the power they would receive with no voltage drop.

should read

If the brakes take 20A then they will get 90% of the power they would receive with no voltage drop.

Member - Stuart P (WA) posted:

run a 5mm twin wire red for elec brakes and the black to pin 2 for fused aux power 5mm is the largest wire that will fit into the trailer plug (standard 7/6 pin)

Member - G N (VIC) posted:

Thanks for info
Regards
GN

Member - Vince B (NSW) posted:

Graham.
You have to run a wire to caravan plug & I cannot see how a twin wire set up would be untidy.
I have used this system in previous 4wd's & don't consider wiring to be untidy.
Vince

Member - Graham H (QLD) posted:

Whatever grabs you.

I actually use a twisted pair of 6mm to activate the brakes, which is a bit of a waste when I see the piddly light wire on the van to the magnets.

May have to rewire them as well.

I have enough wires from front to back without unnecessary ones.

Just seems easier to use a short wire from brake switch to the controller, about 600mm away.