# HID Installation, Voltage Drop...Please Help !



## AAudiA6 (Nov 29, 2006)

So I installed my new HID kit, and the kit uses 35w and the OEM bulb uses 55w, so I have about 20w drop which indicates a BULB OUT light in my dash. I'm wondering if anyone knows what kind of resistor I could put in between to get that difference to make the computer think that there's an actuall 55w draw?
I found this link, similar question do you guys think this will work? 
See diagram
http://www.mbworld.org/forums/...48247
THX


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## Massboykie (Aug 15, 2006)

*Re: HID Installation, Voltage Drop...Please Help ! (AAudiA6)*

Hey AAudiA6
I looked at the link, and from an electronic/electrical standpoint this should work, if you are attempting to cause a small constant current flow across the circuit (through the resistor), which is what I think you need to "trick the computer" in believing the bulb is still glowing. The 35W and 55W does not really have anything to do with this. 
As for the wattage of the resistor... I do not know what the power needs are for the HID part of the circuit... I would assume it's working resistance is much lower than the resistor, so the ballast will flow more current... so, put a 1/2W resistor in there and see if it gets hot. If it gets hot quickly (hot as in you cannot touch it, or worse it starts to smoke), you might want to go to a 1W or even a wire wound resistor (5W and up), as one of the other people mentioned. Before I go up in wattage, I would try a higher value resistor though. 
Looking at the circuit they drew up, I do not think the resistor would harm anything. I would start High though (3K or 2.2KOhms as these people used) and go lower (assuming you have resistor's heat under control). Now if you lower your resistance, you will be increasing the current flow through it, and also the heat it would have to dissipate. So, if it works with a higher resistor, that would be better, i.e. cooler.
RadioShack sells packets of resistors, but you could probably buy these and get away with it... for 2.2KOhm you will be looking for red, red, red stripes (the forth line is the tolerance - gold or silver-, don't worry about that). 3K will be orange, black, red (little higher for kicks) 1.8K (little lower) brown, grey, red and 1K (way lower) brown, black, red
I hope someone else would corroborate my logic, as I not 100% certain... it's been a while since I did any resistance calculations...







Oh, be careful around those ballasts, they probably kick out a hefty voltage on the back end...
Hope that helps
Cheers
Massboykie


_Modified by Massboykie at 12:08 PM 12-5-2006_


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