Tow Bar issue!!

fasteddie1.9 · 22nd April 2009, 11:01

Hi guys

I recently had a tow bar fitted and when the electrics are connected it's causing the bulb failure indication to come on! I think the garage that fitted the tow bar may have connected the electrics into one of the rear light clusters which may be causing the problem. I know on previous cars with CanBus that a tow bar had to be Tech2'd so the ECU and SIM controllers would know why there was more current being drawn and not shut down the bulbs thinking it had failed.

I had a read through a thread I found on here and there was mention of a bypass relay? Where would I find it if I have one? If I don't have one where would I get one and how do I fit it?

Thanks in advance guys!

baxlin · 22nd April 2009, 11:09

The easiest way to find if you have a by-pass relay is to ask the fitters if they used one.

When you connect the trailer lights to the car, and indicate, do you get either a buzzer, or a light on the dash "echoing" the indicator flashes?? One of these is a legal requirement. The bypass relay, or the MGR OE setup will supply one or the other - or both.

So if you don't have buzzer/dash light, I would say there's a good chance you don't have a bypass relay.

I bought mine from Towbars Direct (I think), for around £20, and in their listings the 75 was shown separately, because of the bulb warning, and other, circuitry. Fitting was easy, as an idiot guide was included in the obstructions. The hardest bit was routing a power supply from the front of the car.

HTH

Malcolm

fasteddie1.9 · 22nd April 2009, 11:13

The bulb failure indicator lights up and if I'm indicating the indicator flashes rapidly like old cars used to when there was a bulb out. I can't remember if there was a buzz or not, it was a while ago when I last towed, I'm a bit unsure now with the indicators not working properly with a trailer on, I don't wanna get pulled, lol!

baxlin · 22nd April 2009, 15:49

If it's a while ago that it was fitted, but you assume it's not the MGR OE loom, the by-pass relay will most likely be found amongst the wiring of the rear light clusters, I put mine in the nearside, but it could have just as easily be on the offside.

The cheapest - just to get the buzzer, could be a flattish cylinder about 3" long with about 5 wires going into it. But this wouldn't I would have thought protect the bulb failure circuit.

My bypass relay, is a flat box, about 2 -3" square.

HTH

malcolm

rover · 22nd April 2009, 17:28

Have a look at "Rydertowing" website which lists all the info you need including a Practical Guide to Towbar Electrics.

22nd April 2009, 11:01	#1
fasteddie1.9 Newbie Rover 75 Club Join Date: Mar 2009 Posts: 10 Thanks: 0 Thanked 0 Times in 0 Posts	Tow Bar issue!! Hi guys I recently had a tow bar fitted and when the electrics are connected it's causing the bulb failure indication to come on! I think the garage that fitted the tow bar may have connected the electrics into one of the rear light clusters which may be causing the problem. I know on previous cars with CanBus that a tow bar had to be Tech2'd so the ECU and SIM controllers would know why there was more current being drawn and not shut down the bulbs thinking it had failed. I had a read through a thread I found on here and there was mention of a bypass relay? Where would I find it if I have one? If I don't have one where would I get one and how do I fit it? Thanks in advance guys!

22nd April 2009, 11:09	#2
baxlin This is my second home Volvo C70 Convertible and JZR 3 wheeler Join Date: Nov 2006 Location: Tring, Herts Posts: 3,960 Thanks: 124 Thanked 173 Times in 124 Posts	The easiest way to find if you have a by-pass relay is to ask the fitters if they used one. When you connect the trailer lights to the car, and indicate, do you get either a buzzer, or a light on the dash "echoing" the indicator flashes?? One of these is a legal requirement. The bypass relay, or the MGR OE setup will supply one or the other - or both. So if you don't have buzzer/dash light, I would say there's a good chance you don't have a bypass relay. I bought mine from Towbars Direct (I think), for around £20, and in their listings the 75 was shown separately, because of the bulb warning, and other, circuitry. Fitting was easy, as an idiot guide was included in the obstructions. The hardest bit was routing a power supply from the front of the car. HTH Malcolm __________________ Only my opinion, obviously, so please don’t shoot me if it doesn’t match yours! Last edited by baxlin; 22nd April 2009 at 11:13..

22nd April 2009, 15:49	#4
baxlin This is my second home Volvo C70 Convertible and JZR 3 wheeler Join Date: Nov 2006 Location: Tring, Herts Posts: 3,960 Thanks: 124 Thanked 173 Times in 124 Posts	If it's a while ago that it was fitted, but you assume it's not the MGR OE loom, the by-pass relay will most likely be found amongst the wiring of the rear light clusters, I put mine in the nearside, but it could have just as easily be on the offside. The cheapest - just to get the buzzer, could be a flattish cylinder about 3" long with about 5 wires going into it. But this wouldn't I would have thought protect the bulb failure circuit. My bypass relay, is a flat box, about 2 -3" square. HTH malcolm __________________ Only my opinion, obviously, so please don’t shoot me if it doesn’t match yours!

22nd April 2009, 11:13	#3
fasteddie1.9 Newbie Rover 75 Club Join Date: Mar 2009 Posts: 10 Thanks: 0 Thanked 0 Times in 0 Posts	The bulb failure indicator lights up and if I'm indicating the indicator flashes rapidly like old cars used to when there was a bulb out. I can't remember if there was a buzz or not, it was a while ago when I last towed, I'm a bit unsure now with the indicators not working properly with a trailer on, I don't wanna get pulled, lol!

22nd April 2009, 17:28	#5
rover Loves to post Rover 75 Saloon Join Date: Nov 2006 Location: Staffs/Derbyshire Border Posts: 285 Thanks: 19 Thanked 29 Times in 14 Posts	Have a look at "Rydertowing" website which lists all the info you need including a Practical Guide to Towbar Electrics.