Passengers HID headlamp not starting

[Ck2hans]

Previous owner had headlamps changed to HID's. The passengers side has started not coming on when the engine is started (day time running mode). I can turn both headlamps on at anytime with the switch prior to starting the engine, or once the engine is running I can turn the breaker (in the drivers compartment outside door) off then back on again and the passengers side will work, and continue to work until I shut down the engine. I have replaced both 35W Can-Bus units and both HID bulbs (driver side and passengers side). I have pulled the dash apart and checked the connectors, still have the passengers side not coming at start.

I was told that Can-Bus HID's can have trouble starting if there is low voltage. Considering the power supply for the passengers side runs all the way across the front of the bus and starting the engine does cause a slight voltage drop just when the HID bulbs are trying to start up it kind of makes since. I am thinking of putting a capacitor in line just before the passengers side HID plug in. Any thoughts as to what size capacitor I should install?

Chuck

[Gil_J]

DRL circuits should NEVER be used with HID or LED headlights. Neither are designed to operate at the lower voltage supplied by DRL circuits. Some don't change the high beam and they use the high beam for the DRL. The US has abandoned DRLs. I recommend the DRL module simply be pulled if high and low beams are LED or HID. I believe Canada still supports DRL. I've driven across a lot of Canada with 2 coaches without DRL and have never had a problem and doubt anyone running US plates would have any issues in Canada.

[Ck2hans]

Gil:
Was hoping you would reply with your advanced knowledge of electrical system, because of my weakness in electrical systems. Based on the pictures/drawings attached, what wires do you suggest I remove? Also what are they using the diode between R19 & R20 on the DRL modification.
I am a got to touch & see things to figure them out guy, which we all know you don’t do with electricity. LOL

Chuck

[Ck2hans]

Been experimenting this morning and haven't blown anything up yet.
Referring to the first picture/drawing posted, removed all the wires from relay in lower right of picture #85-#86-#30-#87 and removed wire between R19 & R20. Headlamps work with switch but no DRL as expected. Low beams on, no high beams on. High beams on, no low beams on high.
Reconnected wire/diode between R19 & R20, Low beams on, no high beams. High beams on, low beams also on. With my low beams being HID's they are almost as effective as the high beams that are not HID's. Think I will leave the R19 & R20 with diode connected for more lighting with high beams on. Will this cause any issue going forward?
Chuck

[Gil_J]

Chuck,

I thought I suggested removing the DRL module. Anyway, it sounds like you have done just that. Having both high and low beam on at the same time won't be an issue. They are independently protected.

[Ck2hans]

Gil:
Don't understand electrical wiring enough to know why things were done in the past BUT...
The relay for the day time driving lights was removed and a black wire and red wire were inserted into the #86 & #87 slots (see attached pic). The R19 & R20 have a diode between them per first pic/drawing of this post.

What I have done so far is to leave the day light driving relay out and remove all the added wires including unplugging the diode between R19 & R20. Low beams work with dash switch head lamp switch on but do not come on when engine is started as expected. When switching to high beams low beams go off.

I plugged the diode back in that goes between R19 & R20. Low beams come on with dash head lamp switch and when turning on high beams, low beams remain on.
Seams to work with the dash head lamp switch as I have it now, so I am leaving it as is.

Thanks for the input that the High and Low beams are independently protected. I feel better knowing that.

Chuck