Lights flashing when trailer plug inserted

Here we discuss Hiluxes in general. Your view of the Hilux. For other general discussions please see "open Discussions" under the "Around the Campfire" heading.
Post Reply
User avatar
Posts: 8
Joined: Fri Jan 16, 2009 9:54 am
Town: Cape Town
Vehicle: 1997 2.8D DC 4x4 and 2018 2.8GD-6 Raider 4x4
Real Name: Rod
Location: Cape Town

Thu Jan 10, 2019 4:21 pm

Hi guys and gals

Firstly.... Compliments of the Season to you all. Hope 2019 is a successful year
I have the 2018 Hilux and installed the steel rear bumper (with tail lights) from Safari Centre. Problem I have though is when I plug my trailer in and my headlights are on, the lights on the bumper and trailer flash but not the lights on the vehicle. All the lights work correctly i.e indicators, brakes, etc even when headlights are on, only they flash then, Any ideas? A wiring issue between bumper and vehicle?
I look forward to some ideas
C.R. Smith
+27 76 748 9397

Security, Steel & Decor
You Design it, We Create it

(m) 0767489397
(f) 08607594573
Posts: 5
Joined: Fri Jan 20, 2017 11:01 am
Town: Edenvale
Vehicle: Hilux
Real Name: Chris

Fri Jan 11, 2019 6:58 am

Does the trailer have LED lights by any chance? If it does and they are not setup to be in a CANBUS enabled vehicle, or there is no suitable towbar adapter installed, modern vehicles send ripple current to lights to test if they are working and notify you on the cluster, this can cause LED lights to flash constantly.
User avatar
Mud Dog
Posts: 29175
Joined: Tue Apr 29, 2008 2:18 am
Town: East London
Vehicle: '90 SFA Hilux DC 4X4, Full OME, 110mm lift. Brospeed branch, 50mm ss freeflow exhaust. 30 x 9.5 Discoverer S/T's on Viper mags. L/R tank. (AWOL) '98 LTD 2.4 SFA, dual battery system. Dobinson suspension, LR tanks, 31" BF mud's.
Real Name: Andy
Club VHF Licence: HC103

Sat Jan 12, 2019 8:02 am

Happened to speak to an autolec yesterday and asked about this. According to him it's a very common problem where people try installing a trailer plug on late model vehicles by just tying in to the tail light wiring like we've all done in the past. He also mentioned that it will interfere with the "canbus" and plays havoc with lights and in some cases other electricals as well. Said that there was no way around it and that a trailer plug adaptor / module (cannot remember the exact terminology he used) had to be installed.
When your road comes to an end ...... you need a HILUX!.


Life is like a jar of Jalapeño peppers ... what you do today, might burn your ass tomorrow.
Don't take life too seriously ..... no-one gets out alive.
It's not about waiting for storms to pass. It's about learning to dance in the rain.
And be yourself ..... everyone else is taken!
User avatar
Posts: 12866
Joined: Tue May 22, 2007 10:09 am
Town: Klerksdorp
Vehicle: Hilux DC SFA, Hilux 2.7 DC, Hilux 2.7 SC, Prado 95 VX
Real Name: Eric
Club VHF Licence: HC101
Location: Klerksdorp, NW

Sat Jan 12, 2019 10:10 am

Basically the module comprises either a relay to operate the trailer lights, or a Thyristor, which operates like an electronic relay. In other words, no additional current load is placed on the existing wiring loom other than the drive for the relay or thyristor which is usually inconsequential. The 12v power for the additional lights must be drawn from a dedicated 12v supply.


White Fang: 1999 2.7i DC Raider 4x4
Bull Dog: 1987 4Y-EFI 2.2 DC 4x4
Pra Dog: 1998 Prado VX 3.4
Hound Dog: 2000 2.7i SC 4x4

One Staffie, One Jack Russell, One Ring Neck Screecher, 17 Fish of questionable heritage

User avatar
Posts: 8106
Joined: Fri Nov 26, 2010 7:53 pm
Town: East Rand
Vehicle: IFS Hilux
Real Name: Neil
Club VHF Licence: HC105
Location: 4x4 Direct Boksburg

Tue Jan 15, 2019 8:30 am

Hi, you need to install a wiring harness which plugs directly into the Hilux rear harness.
index.jpg (13.2 KiB) Viewed 238 times
They can be purchased from Toyota, if you don't come right give me a call on 011 823 5319.
Not all those who wander are lost!

Scout motto:be prepared....
IFS is like a swambo, soft, sexy and expensive!
Post Reply

Return to “General Hilux Discussions”