Driving light relay

Deending of course on if you vehicle is positive or negative switched. I would have thought your Hilux would be negative switched so wouldnt need to earth relay to body?

Yeah it is negative switched I put a thread on here somewhere about 12mths ago when I wired them up (an auto sparky couldn't figure out how to do it)

Cheers
Dave

Hi, The diode is only used on releys which are activated by transistors or mosfets as in computer controled stuff. its there to absorb back EMF from the coil in the relay so it doesnt damage the switching device. Not needed for normal swithing as in Spot lights etc. Dareyl

So if i was to upgrade the headlight wiring on my BT50, would i need t use relays with resistors or can i just use the normal relays? Reason being is i have already bought the normal ones, but i dont wanna stuff up anything.

You should be pretty safe, relays, solenoids and coils give of EMF when de-energising the coil, basically the energy stored has to go somewhere and the best place is to earth.

Resistive Relays are better to a certain extent as they are non polarity device, just the same a a normal no protected relay but the will have a larger loading across the coil then a non protected or diode protected one.

In non protected relays EMF will be measurable but in most cases you have the battery to absorb the energy.

Most spike/surge protected relays are switched from direct out puts from the ECU or BCM, ECU's and BCM's will still survive being use with non protected relays as all ECU's and BCM's have their own spike/surge protection.

BUT.....the ECU, BCM inbuilt spike/surge protection may work 5000 times and them the 5001 time the spike/surge will get through causing expensive damage....bear in mind this is the same for protected relays....you hope their protection will last for ever but you just don't know.

We use diode protected relays in all the stuff we do...just in case + dealing in new vehicle we don't want to get caught out, the price difference is about $5.00 a relay.