Projects Headlight relay problem, very strange...

O/T vehicle, but the same could happen to any rod.
Twin headlights, relayed for each beam and each light (4 relays).
Power from battery (straight, fused).
Grounded straight to frame (checked, OK)
Trigger power from headlight switch, separated to each relay.
One unique touch (because it's a bike), I want to be able to shut down each light separately, so I wired the trigger ground to two switches (left relays to one, right relays to the other).

The problem - if I switch on both lights, neither will then shut down, even with the ground AND power shut off to the trigger (85 and 86 terminals).

I am using standard Bosch relays (85 + 86 trigger, 30 + 87 switched power). The only thing I could possibly think of would be slightly low battery power (10.5 volts), due to a lot of testing. I thought of induced voltages, but even after I pulled the wires to both ground and power on the trigger, the relays were still energised. Also, I was able to turn on the relay by simply hitting it, with no trigger power to it, either positive or negative.

Anybody??

Thanks, Cosmo

 

Forgot to mention - can't get it to do this on the bench.

 

Sounds like the relay coils are slightly energized at all times, when you hit them they pop on? And they stick on?
Check for 1/2 battery voltage at the coils, maybe you've got them wired in series and always hot.

 

Problem was solved with diodes in each trigger positive. There apparently was some feedback through the coils, the diodes eliminated the backfeed.

Cosmo

 

Use separate switches!