HID questions

[stussyjoo8]

Hi guys, I have couple questions regarding HID kit for my 2011 mazda 3 gx.
I am going to get 35W HID kit but do I still need relay harnesses?
some people says yes and some says no.
and also, do I need Capacitor?

[rzapata]

Not sure about this but I think the 2011 have the high beams as the DRL. If that's the case then you probably don't need a relay harness because the HIDs will be receiving full power once the low beams are on anyway.

[m3thods]

I was in the same position as you- from all the mazda3 forums I've read, only a handful of people ran harnesses. I'm currently using a 35W kit and have no issues. All my friends running mz3's and HID kits are running 35W kits with no harnesses and no issues. IMO, it's just extra wiring that needs to be hidden.

There were a few posts floating around on the web regarding their need: some people say that it's a failsafe against ruining your stock wiring. Some people say they're actually useless (something about most relays using a single 25A fuse, and that there is no protection for 15-20A where potential damage can occur).

Your best bet is to read up on it some more and make a decision based on that. One thing I suggest is that if you are buying a "cheaper" HID kit, try to find out what the amp draw is upon a cold start. I've read that it can get upwards to 13A, which may or may not strain the stock wiring. Some of the more expensive kits (XenonDepot, Philips, Morimoto) advertise ballasts that are "low-draw", meaning draw no more than 4-5A.

Of course ymmv, but I don't think they're necessary.

[McGuyver_3]

2007-now no parts needed plug and play
2004-2006 either a relay or a cap or both will be needed. All depending on your preferences

[zoomahh]

I was in the same position as you- from all the mazda3 forums I've read, only a handful of people ran harnesses. I'm currently using a 35W kit and have no issues. All my friends running mz3's and HID kits are running 35W kits with no harnesses and no issues. IMO, it's just extra wiring that needs to be hidden.

There were a few posts floating around on the web regarding their need: some people say that it's a failsafe against ruining your stock wiring. Some people say they're actually useless (something about most relays using a single 25A fuse, and that there is no protection for 15-20A where potential damage can occur).

Your best bet is to read up on it some more and make a decision based on that. One thing I suggest is that if you are buying a "cheaper" HID kit, try to find out what the amp draw is upon a cold start. I've read that it can get upwards to 13A, which may or may not strain the stock wiring. Some of the more expensive kits (XenonDepot, Philips, Morimoto) advertise ballasts that are "low-draw", meaning draw no more than 4-5A.

Of course ymmv, but I don't think they're necessary.

You have read right re; the general consensus says no for relay harness...But being as I'm a fan of OVERKILL, 'an ounce of prevention is worth a pound of cure" (ya you young pups probably never heard of that one :), and all those other ole sayings about fail-safes. Method did mention that the Morimoto kits draw very little power, and they are one of the better ones out there. He's right. I have the 35w 6k hid with their dual relay heavy duty battery harness (only $ 30.00 for the harness by the way..... It's got 2.. yes TWO 40Amp relays with an inline fuse ta boot. yup....I luuuvvvv safety (breathes on fingernails n rubs on shirt collar smugly)

If you like safety?.. defined as spending over 20G's on a financed car that in case you didn't know, your insurance WILL NOT cover tampering with electrical vehicle wiring (AKA stupidity or negligence)found as the cause of your precious car burnt to the ground, hence if you have no protection, and now NO car, your shit is in the wind, your bankrupt and now having to resort to taking the "peasant wagon" (TTC), for the next 10 years while your stuck paying off a car that you burnt to the ground and is now a rusting hulk in some junkyard kinda safety?......hmmmmmm lemme think..... I would D E F use a battery harness and consider it $30.00 worth of safety (your ounce of prevention)....but that's jus me ;)

[McGuyver_3]

You have read right re; the general consensus says no for relay harness...But being as I'm a fan of OVERKILL, 'an ounce of prevention is worth a pound of cure" (ya you young pups probably never heard of that one :), and all those other ole sayings about fail-safes. Method did mention that the Morimoto kits draw very little power, and they are one of the better ones out there. He's right. I have the 35w 6k hid with their dual relay heavy duty battery harness (only $ 30.00 for the harness by the way..... It's got 2.. yes TWO 40Amp relays with an inline fuse ta boot. yup....I luuuvvvv safety (breathes on fingernails n rubs on shirt collar smugly)

If you like safety?.. defined as spending over 20G's on a financed car that in case you didn't know, your insurance WILL NOT cover tampering with electrical vehicle wiring (AKA stupidity or negligence)found as the cause of your precious car burnt to the ground, hence if you have no protection, and now NO car, your shit is in the wind, your bankrupt and now having to resort to taking the "peasant wagon" (TTC), for the next 10 years while your stuck paying off a car that you burnt to the ground and is now a rusting hulk in some junkyard kinda safety?......hmmmmmm lemme think..... I would D E F use a battery harness and consider it $30.00 worth of safety (your ounce of prevention)....but that's jus me ;)


Talk about scaring the crap out of people that ask questions. :chuckle

[zoomahh]

Hey Dan.... :pofl
Sorry to the op but if you knew me, you would find out that I'm a black n white kind of guy. . . there is NO grey area, no BS. . no beatin round the bush. . . I tell it like it is :) . . hmmm ...maybe I should apply for Don Cherry's job :P . . sorry... back on topic

To the OP;
If you have any doubts whatsoever about your install. . And from what I can tell, you have done your due diligence as far as reading forum stuff goes, I recommend going with a battery harness . . .period! ! So basically what it does is it adds an extra fuse (aka protection) between your kit and your precious baby. And I'll go one further by saying browse to the morimoto site and look up their heavy duty battery harness. . .lemme tell ya bro, as soon as you see that badass mofo, you'll want one asap! ! This battery realy harness SCRRREEEAMS the word SAFETY. If there are no sponsors here on the forum that distribute the morimotos, I have a dealer here in Ottawa that sells em and I can hook you up ;) cool?

[McGuyver_3]

So you like throwing away money?
There is no need for relay harnesses. I have tampered with mazdas since 05 and many other models since 05. On the 3's yes relays were necesary on 04-06 models UNLESS you decided to simply connect them in to the amber corners. Which worked but when the ballasts started to go they POPPED FUSES and caused no further harm. On the 07 to 09 models all the lowbeams are protected by 2 seperate 10 amp fuses. I assume the oem xenon would be the same amperage but they MAY have gone 15 amp fuses each. However wiring size stayed the same. How do I know this? I played with those cars A LOT. The 2010 and up I haven't looked in to the headlight schematics as of yet as I had no need to but as far as safety reasons go regulation wise they should always be on seperate fuses anyways. By all means, you want a relay harness go ahead but from my experience and the things I have tampered with the OEM system has never given me a problem knock on wood. Of course this is all based on each vehicle application.

[zoomahh]

@ Stussy; I would then differ to McGuyver on what he says here then. His knowledge of the Mazda electronics are light years above mine, which are limited ;) . However if you have never installed hid's before, one thing I would recommend is have someone that has done it before, help you with it, or do it for you. OR if you can get McGuyver to do it, your worries are over....

@ Dan; your right about the 07 fuse thing. There's a fuse in the engine bay and in the one under the glove box. Thanks for chiming in on this one ;)

[m3thods]

I'm no electrician or car nut, and forgive me if I'm wrong-

But what's the point of having 40A fuses in your relays? My understanding is that fuses break if more current is run through the connection. That means that you would need >40A to break the fuse in those relays, right?

IIRC, draw from stock halogens from cold start is ~15A (again this was read on a forum, not from a manual, so this could be wrong). So wouldn't having 40A fuses have provide too much lee-way in terms of electrical tolerance for the system? Wouldn't it make sense to have 20A fuses to be "safer"?

Don't get me wrong I'm not trying to pick a fight with you. I'm just trying to work it out for myself, as I have relays in my bedroom that I didn't connect (came with my XenonDepot kit). :) It's not THAT much more work to put them in if I'm wrong :P


You have read right re; the general consensus says no for relay harness...But being as I'm a fan of OVERKILL, 'an ounce of prevention is worth a pound of cure" (ya you young pups probably never heard of that one :), and all those other ole sayings about fail-safes. Method did mention that the Morimoto kits draw very little power, and they are one of the better ones out there. He's right. I have the 35w 6k hid with their dual relay heavy duty battery harness (only $ 30.00 for the harness by the way..... It's got 2.. yes TWO 40Amp relays with an inline fuse ta boot. yup....I luuuvvvv safety (breathes on fingernails n rubs on shirt collar smugly)

If you like safety?.. defined as spending over 20G's on a financed car that in case you didn't know, your insurance WILL NOT cover tampering with electrical vehicle wiring (AKA stupidity or negligence)found as the cause of your precious car burnt to the ground, hence if you have no protection, and now NO car, your shit is in the wind, your bankrupt and now having to resort to taking the "peasant wagon" (TTC), for the next 10 years while your stuck paying off a car that you burnt to the ground and is now a rusting hulk in some junkyard kinda safety?......hmmmmmm lemme think..... I would D E F use a battery harness and consider it $30.00 worth of safety (your ounce of prevention)....but that's jus me ;)

[McGuyver_3]

@ Stussy; I would then differ to McGuyver on what he says here then. His knowledge of the Mazda electronics are light years above mine, which are limited ;) . However if you have never installed hid's before, one thing I would recommend is have someone that has done it before, help you with it, or do it for you. OR if you can get McGuyver to do it, your worries are over....

@ Dan; your right about the 07 fuse thing. There's a fuse in the engine bay and in the one under the glove box. Thanks for chiming in on this one ;)

From my understanding he says the relays are capable of withstanding 40amps of current through them. When people have asked for relays to be put in I have seen as low as 15amp fuses to a max of 30amp fuses installed for both power wires to the ballasts on the same fuse.
As for the max fuse rating the fuses are generally upped by 15% and if that number lands on an odd baller number it goes to the next common fuse available.