Headlights relay and LED bulbs

[David R]

I have got the conversion to Halogen headlight on my Dolomite 1500HL and I understand that I should put in a relay as part of the conversion? If I use LED bulbs instead (drawing less power) would I still need the relay? If I need to use relay, where should it go? Could any answers be at 'numpty level 3' please (not good with electrics) Thanks.  

[Pete Lewis]

some headlamps will not be legal with LED bulbs    need to do some homework on this subject .

relays can go anywhere the harness will allow .

you use relays to improve the voltage drop of the old wiring and reduce the current at the switches.

led use much lower current and dont need relays as such , but you do need to be clear on fitting to 

your current lenses is ok , this was discussed a while back ,  both bulb types will fit but led 

can add complications and MOT problems later 

Pete

 

[Nigel Clark]

The right type of LED headlight bulb should meet MoT requirements, including correct dip pattern for RHD. I've fitted headlights from this helpful company to my TR6:

https://www.classiccarleds.co.uk/collections/headlight-led-bulbs

Relays aren't necessary since LEDs use less current and are less voltage sensitive than traditional tungsten or halogen bulbs.

Nigel

[Mjit]

While you probably don't need a relay with LED headlights it's not going to hurt to fit one.

As for where to fit it I don't know the Dolly 1500 wire diagram but I'd bet there's a 4-way bullet connector just behind the front panel where a single feed wire splits into two wires, one to the left headlight the other to the right.  Given where the battery sits I'd bet you can find a convienient bolt near it to mount a relay+inline fuse then you can:

1. Unplug the current, single 'input' wire from the 4-way connector.
2. Connect that to the input side of the low current/switching side of the relay (normally pin 86) + a new earth wire from the output side of the low current/switching side of the relay (normally pin 85) to a convienient earth point.  The light switch now powers the relay switching circuit.
3. Connect a new wire from the battery +ve terminal, via the inline fuse, to the input side of the high current/swiched side of the relay (normally pin 30) + a new wire from the output side of the high current/switched side of the relay (normally pin 87) to the newly vacated hole in the 4-way bullet connector.  You now have a direct battery->fuse->relay->headlight circuit.

 

Edited April 16 by Mjit

[David R]

Many thanks to all, I now have a way forward👍