Guest Anonymous

Solution to installing relays on low and high beams

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Guest Anonymous


If you have upgraded your headlights to H4s and have a warm or hot headlight switch stalk(the metal stalk behind the plastic knob, Dave at Susquahanna Motorsports gave me a solution and helpful wiring diagrams that are on his website.

The attached link to a wiring diagram on his web site gives the wiring schematic for adding relays to high and low beam.

Additionally, he sells an adapter (his part number 66490) that connects to the back of the H4 and with a little "finigiling" the other end of this adapter may cut off and used to insert into the original connector to the headlights, and you do not have to cut any original wiring. There is also a link to that adapter

He also sells the relays and a really cool relay bracket. The bracket mounts to your inner fender well, the spade tip wires go into the bottom of it, and the relay plugs into the bracket. It is a real clean set up and if you need to disconnect or replace a relay, it is plug and go. There is als a fused edition too.

I know my discription is criptic, so if you get into this, Dave is a good guy and will walk you through it. His number is 610.944.3233

This will take a great load off of the switch and cool it down for those having a hot switch.

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Guest Anonymous

I scarfed up a Range Rover relay bracket / plug from one we were dismantling for parts - it sat just to the left of the steering collumn, and just under the dashboard. (No idea what year - sorry)

THIS one takes a std Bosch / Hella 4 or 5 pin relay - and has a tab to mount it to the firewall or inner fender. What makes this particular one super slick - is it has a FUSE recepticle built into the side of it!

I used the genuine BMW female spade connectors soldered to the wires - the type that lock into the connector - for minty freshness.

Installed it on my car for the electric engine fan - and the thing is slicker than snot IMHO.

If I recall correctly - all German relays (4 and 5 pin) can be set up to be wired as such:

85 = to chassis ground

87 = to accessory (lights, horns, fan, etc)

87a = to other side accessory (if desired, like one for each headlight, horn, etc)

86 = from controlling switch power

30 = battery power supply

I've heard a safer way to wire the circuit - is to have the switch complete the GROUND circuit - not the power circuit - which would obviously change the above designations somewhat.



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