Background:
I am retrofitting NHK G5 bi-xenon's into my truck, ballasts are Hella aftermarket 35W, bulb is Hella D2S, Motocontrol relay 9004/9007. The wiring in the truck is all stock at present. I previously replaced the headlamp switch and plug pigtail as well as the multifunction switch. Neither of them appear to have any visual fault/short.
The problem:
Twice now I have smoked out the motocontrol relay. I turn on the headlamps with the truck running and they come on. I engage the high beam, one HID goes out and shortly thereafter the relay smokes. Before I smoke another relay I'd like to figure out what's going on. I checked function of the headlamp circuit with the engine off as well as running. I have trace voltage (~.18V) w/ Hi Bm off, Low on or vice versa with the engine off and about ~1.8V w/ Hi Bm off, Low on or vice versa with the engine running. I was thinking this might be enough to trip the relay back and forth, but was told that the relay triggers at 10V. I've checked the headlight and multifunction switches. Neither one looks to have shorted or burned out. Looking over the harness I haven't found anything that would be causing trace voltage or a short. The fact that the issue occurs going to high beam suggests multifunction but like I said, I checked it on the bench and seems to work fine. Anyone have any thoughts? I'm really frustrated and scratching my head. Any input would be MUCH appreciated.

 

Your truck came with 9004 bulbs, 9007 are wired different.... Real possibility you have polarity reversed somewhere.

 

I understand that, I made sure to change the wires on the Motocontrol plug. That wouldn't be polarity reversed, but a crossed circuit.

 

Does the dimmer switch on your control the power side of the circuit, or the ground side???

 

Power side

 

Think I'd be checking that polarity was correct on the bulb that goes out when you hit the high beams.....

 

does the system have a dedicated ground, I would wonder about a back feed causing trace voltage

 

Nice choice, I will be using the G5N. Almost identical but I like the G5N better. Just a short explanation of how HID projectors work. The bulb stays on both high and low and a shutter moves during high beam to allow more of the projected light out higher(high beam).


The Motocontrol you have should keep the bulb on during high and low circuits. You can look at the instillation instructions here. I assume you have a 12V tap on the battery and ground hooked up. Are you taping into the old bulb output plug or off the headlight switch? Use the old buld plug wires and test them prior to hooking them up.
Something is not wired correctly.

 

Did the same side turn off both times when you switched to hi-beam ? Wondering if there's something wrong with the projector mechanism or maybe the wiring harness on that side. I'd figure out the connector pinout at the relay side and use fused wire from the battery to power up the individual circuits.

 

Who sells these? Quick search gave aliexpress and some Polish page