Tr4 Headlamp Relays

[Bob Horner]

Thinking of fitting headlamp relays. Not sure whether to run a new supply all the way to the lamps and fit relays near the lamps or site the relays near the dip switch and thus use most of the existing wire to the lights with a new supply only going to the relay somewhere in the footwell/bulkhead.

 

The existing lights seem fairly bright so doesn't seem to be much of a voltage drop and main aim is to help out the switch, also the bulkhead relay is less "invasive". However, part of me thinks it is better to use more new cable with a higher current capacity. Also, if the relays are up front, are there issues with keeping them weather proof? Where do people site them?

 

Thanks in anticipation

 

Bob

[BlueTR3A-5EKT]

For the sake of tidiness I positioned my relays above the pedals with the relay switched power using the existing headlamp loom. The feed in is simple at the floor mounted dip switch. The main power comes through its own fat lead from the battery and a fuse.

 

The right way to do it is of course beef up all the wiring feeding the headlamps I guess.

 

Cheers

Peter W

[John Morrison]

Hi Bob,

 

Great Mod, and I fitted my relays, near the off side headlamp using existing supply,

easier to chat give me a ring 01228 548205.

 

John.

[Steves_TR6]

I'm with john.

 

I fitted relays , admittedly to a 6 not a 4 , by the ns headlamp.

 

This way no cutting of the existing wiring is required, and the new power wire replaces more of the old wire.

 

Steve

[RogerH]

Hi Bob,

the cable already in the loom is man enough for the lights. As you say the switch is the vulnerable item.

 

I fitted two relays in the engine bay on the rear side of the offside wheel arch. There a convenient flat space for four/five relays

Also the loom is very close by and easy to work on.

I used the wire from the swtich (dip switch) to power the relay. The other half of the cable went to the lights as normal from tyhe output of the relay.

I then fed a good sized wire from the starter solenoid battery terminal to the input to the relay (30)

The relay earth goes to the earth point on the inner wing or to the horn attachment screws.

The relays are themselves quite weatherproof but some thought to the connectors may be worthwhile.

I also fitted a modern flasher unit in the same place.

 

Roger

 

 

Edited October 13, 2013 by RogerH

[Bob Horner]

Thanks chaps. I fitted relays close to the lamps on my spit (ie as per John and Steve) and it made a big improvement to the lights - presumably there was a fair bit of voltage drop and running new cable helped. However, tbh the TR lights are pretty good in my opinion ( not halogen good but as good as my relayed spit lamps) so I am not sure whether running new cable as far forward as poss will make much difference. I seem to have all the alternatives - at the lights, at the dip switch and about halfway (Roger). Looking at the car this evening, I think it's either Roger's suggestion or Peter's (near dipswitch) mainly on ease and weather proof ness but if anyone else wants to weigh in with cogent reasons for the upfront position, please do - not bought the cable yet!

 

Cheers

 

Bob

[Ade-TR4]

"7VC" has a very neat arrangement of relays. Worth taking a look at.

 

Ade

[keith1948]

Hi Bob

Fitted the Moss headlamp relay kit (comes complete with fitting instructions) to my TR4A. The relays fitted near fusebox & control unit in engine bay. Uses a lot of original wiring. Made tremendous difference to headlamp brightness. Decided to do this after one of our group fried the switch wiring on his car. One of the best mods to the car I've made.

keith