brian76

I have Bosch relays for my headlights. Problem is , I don't have any idea which wire goes into which port in the relay. Any ideas? Thanks

'75

On those cube relays, 30 is power in, 87 is power out to headlight, 85 is ground and 86 is power from the headlight switch or dimmer switch.

Richard454

This might help-

Jebbysan

This is exactly right.......30 turns the relay on.....86 is the main hot in and 87 the main hot out.

Jebby

lionelhutz

At least you got the 87 terminal right...

Jebbysan

That is what I get for posting before coffee.......early in the morn....

I had 30 and 86 swapped in my head......

Jebby

brian76

On the Bosch relays, how many amp fuse does this use? I know that they're 30 watts apiece, but are unsure of what size inline fuse to get

brian76

What about ports 87a and 30 ? Are they connected together or do I use 2 separate wires?

lionelhutz

Fuse is based on headlight load. If you run 2 headlights then 30A is likely required. FYI, DOT regulations require protection that automatically resets on headlights in case you care about that kind of thing.

87a won't be used.

7T1vette

87a is not connected. The 'line' between 30 and 87a is the internal switch in the relay. As the relay turns on/off, the switch floats between 87a (off) and 87 (on).

P.S. Nice schematic, Richard....

theandies

In my circuit I'm using 20amp fuses but I just recently change out the fuses with 20amp self resetting circuit breakers that fit in the blade type fuse holders.



I'm using three relays. One for regular low beams, one for high beams and one for the high beam filament in the low beam bulbs. Probably overkill but it makes my regular low beams independent of the high beam circuit. I think it's a bit safer.

My alternator puts out 14.61 volts and with my upgraded wires to the bulbs I'm getting full voltage at the bulbs. Both low and high beams are halogen bulbs. With my setup the low beams (35 watts both low and high beam filaments) on they draws 4.87 amps - 35/14.2=2.39x2=4.87. My high beams (50 watts) draw 3.42 amps - 50/14.61=3.42x2=6.84 and since each circuit is independent that is the full draw all the time. I could use 10amp circuit breakers but I chose to keep them 20amps so I have a little more fudge factor. Also installed ceramic plugs at the bulbs and with my setup I have several upgrade possibilities.

My circuit:

Richard454

Nothing wrong with overkill!!!
I actually am running a relay per light- like the Germans do separate circuits for each side.

However- I did upgrade to some Hella's with 80/100watt low/hi and 100watt high bulbs-

Relays fit neatly next to the electric headlight motors where the old vacuum actuator was-and if you look closely the black pieces between the 15A fuses are Ford diodes to isolate Hi and Low beams to run the headlight motors.

And ran some 4GU to power everything up front (headlights/electric headlight motors/horns/dual fans)

theandies

Richard - I remember your setup from some other headlight relay threads.

Kid Vette

Daniel Stern Lighting

brian76

This is exactly how I wired mine. Made a hell of a difference ! Thanks fellas