help needed with wiring for driving lamps

[anonymous-user]

I'm trying to fit a pair of Ring driving lamps to a 2002 Corolla, but I've got stuck with wiring in the relay to the main beam circuit. I'm using a Ring wiring kit, the right one for the lights.

I've done this before a long time ago - 12v fused & earth to the relay on the spotlight circuit, and main beam & earth on the relay switch ciruit to activate it. Easy. So I thought....

The main beam has a separate bulb with a 2-wire plug - black and red. I connected the relay switch feed to the red wire. However if I then earth the relay it clicks on, even with all headlights off. Turning headlights / main beam on does nothing to the relay, it stays on until I remove the earth. I've not yet got the spotlights / 12V main feed connected up.

I then got the multimeter on the plug and if I check for DC 12v to battery earth then both terminals on the headlight plug show 12v even when the headlights are off. I was expecting 12v to just one wire of the headlight plug only when main beam is on.

Can anyone point out my undoubtedly stupid mistake please???

[Steve_D]

What are the pin numbers on the relay?
30 should be your heavy supply in for the driving lights
87 should go to those lights
86 should be the trigger from the high beam
85 should be earth.

Steve

[anonymous-user]

Yes those are numbers that it has, and that's how it's wired up, just suprised to find +12V at both wires in the main beam lamp plug.

[bertelli_1]

Sounds like its switched on the earth - ie:
12v-bulb-switch-earth, rather than 12v-switch-bulb-earth.

Trying to tee into the earth side of the switch wont work, the easiest solution is to wire them to an additional switch, but check the relay, you may be able to use a 12v from there.

[Steve_D]

JimSuperSix said:

.....just suprised to find +12V at both wires in the main beam lamp plug.

If the system has live at the lights then earths the other side to switch them on then you must test for +12v with both headlights disconnected.
If you test with it connected you will so +12 into the lamp and +12 having passed through the filament. likewise if the headlight on the other side of the car is connected the +12 will come through that filament and across the car to the terminal you are testing.

Steve

[anonymous-user]

Done a bit more searching and it seems that Toyota do use a switched earth system as bertelli_1 suggests, so I should be able to wire the earth side of the relay switch circuit into the other headlamp wire and it will then only be earthed and thus turned on when the main beam circuit is earthed.

Getting to the other headlamp bulb is a pain in the neck as it means removing the battery and all the fun and games that entails, so if I can avoid that then it will be better.