Hella 500ff Upgrade to 100w issue

dirtyRU

dirtyRU

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Dec 11, 2010
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Loveland, CO
Alrighty, so i finally have an issue to ask about on here. I installed a pair of Hella 500ff back around Christmas time. I wired them into the fog lamps since it was by the easiest thing to do & there's already a switch on the dash. I figured combining the 500's with my fogs & normal headlamps would give me more than enough lighting, which it has. I got to reading on many of the other subaru forums about how people have upgraded the bulbs to 100w with no over heating issues.
So i went & picked up a pair of H3 bulbs to swap them out. It's simple since there is only one wire to disconnect. I figured it was fool proof, right!? Well i got the new ones in, went to try them out & nothing:eviltoyou:..... Not even my fogs turned on. The switch on the inside still illuminated, but the spotties & fogs stayed off. I checked all the fuses to make sure one didnt blow when i turned them on, but they all checked out fine. So i went to put my 55w's back in & still nothing.
I'm sure this has to be something simple, but i'm no mastermind when it comes to wiring.
Any suggestions?
 
I suggest you use a fused relay, with the wire powering the foggies (my preference would be high beam) as the switch wire for the relay. Make sure this wire is positive, as sometimes Subaru switch the negative. The standard wiring is only big enough to cope with what Subaru had in mind- there is not much left over- certainly not for high draw current things like lights. I wired up my driving lights to come off the high beam wire- that way you can dip your lights with just one switch- which is by far the easiest and quickest way to use them. You can check if the wire is positive with a test light. Clip to the negative terminal of the battery, remove the plug from the back of the headlight and turn on high beam (don't rely on the flasher). If it is switching positive, the light will glow when it is connected to the high beam wire. f it is switching negative, you will need a different type of relay. But you must have a relay and it must be correctly fused and you must run reasonably thick wire- not the anorexic stuff Subaru use. Also, ensure there is no chance of wires rubbing against metal- or anything else. Finally, make sure the lights are earthed- or they will never work
 
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+1 use a fused relay coming off your high beams.

You might find a few of us here mentioning running them off high beams only - that's because it's actally illegal in Oz to wire up driving lights to be active on a low beam/fog setting, but you mightn't have to worry about that part of things.

Cheers
 
did you check all the fuses with a ohmmeter/mutimeter? did you check the fuses under the bonnet? find out which relay the foggies use and check the current rating on it. upgrading your spots to 100W will increase the current draw to 25 Amps with the foggies on aswell
 
Great, Thanks fellas. I think i'm going to try & get this thing rewired to the high beams.
 
Fused relay is the way to go. That's how I did my driving lights. I tapped into the side marker feed for the relay control so they come on when the parking lights are turned on.

I suggest you try to do a reset of the electrical system. Over the past decade, car makers have been shifting to "smart" control of circuits that sense issues in circuits. Disconnecting the negative on the battery over night will in most cases reset circuits that have been turned off.
 
Thanks Prop, I'll give that a shot as i still havent been able to find out why my foggies won't turn on.
 
Think i figured out why the lights don't turn on at all, even after putting the normal ones back in. I overlooked the fuse relay for the fog lamps the last go around. After i took it out, i tested each plug set (as there is a copper plated pair & a normal stainless pair) with my normal fuse tester. It lighted up when i tested the normal pair, but when i touched it to the copper ones, it did not light up. Would this mean i fried the sucker!? This is probably a retarded question for most of you, wiring is just not my specialty!
 
Hi Matt. Sorry- I'm a bit confused, and I think your terminology is a bit different to mine. Make sure that the parking lights and tail lights are still working. If not, check their fuse and replace as necessary. I'm not sure what model your car is, but I don't think my car has the body control module referred to above which can control these things. It is really a case of finding where the power is and work forward from there. I tend to think of things where we have positive switching, so just reverse things if negative switching.

So, the fog light relay in order to switch on the fog lights needs power from the headlight switch (Unless in the US your laws are different) and also from the foglight switch. Each source will probably have a separate fuse. I would imagine that there should be a main power source for the relay, so check your fusible links, SBF (slow burn fuses), etc. Remember, a relay is no more than a fancy switch which is operated by electricity rather than your finger. You use low current wires to switch on or off high current wires.
 
I'm pretty sure you are right about my terminology being off. The piece i am speaking of just says "relay" on it with a part number on it. It lives in the fuse box under the hood with the normal bus fuses. This one just happens to be more of a plug style one.
I hadn't checked the other lamps around the car besides my head lights, fogs, and spotties so i will be sure to do that first thing in the a.m. I've found this plug has gone out on several other subarus associated with the fog lamps, so im hoping thats all it is. Part#82501AE03A.
 
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