Diode Conversion for All Lights On High Beams

Discussion in 'How-to Guides' started by dsfloyd, Oct 13, 2010.

  1. dsfloyd

    dsfloyd New Member


    99'HEARTBEAT Moderator

    X2....On The Write-up being A Sticky.....Best one I have seen,Nicely Done.
  3. judsteele

    judsteele New Member

    i also thought this was a good idea, but make sure you do it right or you will be without lights at night, and cops love that!!!!
  4. Thanks for the link dsfloyd. Great write up there. I want to do this with my 2007 Silverado Classic. It seems like the same set up, but then there is this "IMPORTANT NOTE: This will NOT work for 2002 or 2007+ models..." I will have to dig around the fuse box and check it out tomorrow. Anyone know why this may not work in the 02 & 07 models? I know this is for an Avalanche, but it seems to be the same set up as my silverado. If anyone knows more about this please fill me in because I would like to do the all on hi. Or at least do the fogs on with the high beams. I do overnight trips to Michigan a couple times a year so they would be nice on the quiet highways and back roads. Thanks
  5. Did this mod tonight. Everything was the exact same on my 07 classic. Works good and it was an easy install. Took about 20 minutes with me going extra slow and double checking everything. Getting the relays back in was a squeeze but that was about the hardest part. I'm not too sure if I am going to keep the Full DTRL, but I love the All On Hi already...
  6. JonTiffany1

    JonTiffany1 New Member

    i did this mod too. i will have to upload pics asap! lol

  7. dsfloyd

    dsfloyd New Member

    Glad the mod worked on the 07 friggin noodles. yeah when I did mine I didnt do the DRL's on all the time. just did fog on with low, lows/highs/fogs on.
  8. 97killverado

    97killverado New Member

    Would like to do this on my 97 silverado but I don't kno how. I want to do it this way instead og confusing wiring lol
  9. SurrealOne

    SurrealOne Former Member

    I've been irritated by having to manually turn my fog lamps on each time I start the truck at night and the instructions provided here allowed me to ascertain how to have fog lamps automatically come on with low beams ... as well as have my low beams remain on when my high beams are engaged. The entire process from start to finish took me less than 10 minutes (including testing). I didn't bother with DRL's because they're not bright enough to be relevant in my equation...

    I agree this should be stickied, because anyone who can read and follow directions can get this done ... and someone with half a brain can pick/choose which portions of it are relevant to him/her and do only those pieces. The link provided by dsfloyd provides instructions on what to get (specific diodes), how to prepare them (heat shrink and trim them), and perfect step-by-step instructions on how to install them.

    Much thanks for the link!
    Last edited: Nov 9, 2011
  10. aloxdaddy99

    aloxdaddy99 New Member

    Anyone do this with a newer truck? I have an 11 and would like to have the fogs come on automatically.
  11. SurrealOne

    SurrealOne Former Member

    I've only seen write-ups for 07 and older vehicles. I don't know NNBS trucks, at all, but supposing NNBS still have an under-hood fuse box and also supposing NNBS still use the same relays (in a relatively close cluster like they are in 99-06's) for high/low/fog lights, then extrapolation of these instructions should let you get the job done. (Note that the instructions didn't tell me how to have fogs come on with low beams, but it was intuitive enough when I saw what was being done and how.)

    If you're willing to take a shot ... knowing that you're in uncharted waters and knowing you accept the risk for any/all things you do, then read onward...

    Read the linked instructions (http://www.chevyavalanchefanclub.com/coppermine/albums/userpics/25638/ftdrlnstall.pdf) thoroughly so that you are familiar with the relays, their holes, the location of the holes, etc. Once done, locate the under-hood fuse box of your NNBS truck (presumably it still has one!) and check the diagram on the underside of the lid to see if you can find relays for HDLP-HI, HDLP-LOW, and FOG LP. (Important: find the relays, not the fuses. Hopefully their denotation hasn't changed ... or if it has, it's intuitive.)

    If all three relays are within a few inches of one another then you have a good sign. Your next step should be to see if the HDLP-HI and HDLP-LOW relays are the same (look at the numbers on the relays) ... while the FOG LP relay has a different number. If so, then we're on the right track and have a good bit of parity with the 99-06 relay setup. You last step before determining it's worth trying should be to remove one of the relays and check the underside of it to make sure the pin holes are marked and that they match the same pin hole notation as the 99-06 relays. (I wouldn't expect a visual shape/size match to be enough, as I've seen relays shaped differently that had the exact same pin notation and did the same thing. So check the pin notation.)

    If everything, so far, is a match then you're likely good to connect the heat-shrink wrapped N194 diodes as follows:
    * From hole of HDLP-HI to FOG LP
    * From HDLP-LOW to FOG LP
    * From HDLP-HI to HDLP-LOW (Only if you want low beams AND fogs on with high beams; skip this diode if you don't want that.)

    Understand that a diode is simply a semi-conducting device that allows current to flow in only one direction, thus the black stripe of the diodes should be on the FROM side of the connections you're making. Also, you'd only use ONLY the 85 hole of the any/all of the relays you work with, for this.

    Last edited: Nov 9, 2011
  12. aloxdaddy99

    aloxdaddy99 New Member

    Surreal thanks for the help. Me and electricity don't get along to well. I had a 440v cord arc in while I was plugging in a line a few years ago so I am a little gun shy when it comes to electrical work.
  13. CowsPatoot

    CowsPatoot New Member

    I jumped on here to ask about this exact mod, and I am glad I did some searching before posting. But...it has raised a question. In pic 10 of the PDF (the one that shows all 5 diodes), wouldn't diodes 1 and 3 be redundant? If Diode 1 were removed, the fog lights would still come on with the high beams because it would get the signal through diodes 2 and 5. If Diode 3 were removed, it you would still have FTDRL through diodes 2 and 4.

    I know, I know...I tend to over-analyze these kinds of things. But I won't put my truck at risk by blindly following instructions that I don't fully understand...and just because you find it on the internet doesn't mean it is accurate.
  14. SurrealOne

    SurrealOne Former Member

    I'm still running the mod and it's been fine for weeks. (As always, though, modify at your own risk.) I'd suggest putting the diodes in and testing them one at a time (as I did). You can do them in any order you like...
    Last edited: Dec 1, 2011
  15. dsfloyd

    dsfloyd New Member

    I think you are right. I think the picture is more descriptive of adding diode 5 for fogs with lows. right above it says to do it in the combinations based on what you want. but yes I think if you just wired like the pic those would be redundant. I think it more showed all the combinations on one pic moreso that do all 5 like that. Not sure if it would hurt but its meant for combos. as stated before in the thread, on mine I have diodes 1,2 and 5 but probably could do with out 1, looking at it more closely, since I have fogs with lows and highs and lows with highs.
  16. 5Cent

    5Cent New Member

    Ran this mod on my 01 Duramax for 3years....loved it!

    Now I wish I could figure out a way to have the fogs on automatic and all lights on in the new 2011.
  17. SurrealOne

    SurrealOne Former Member

    If the 2011 uses relays for each then the same concept should apply. If not, educate me -- what's it use?!
  18. aloxdaddy99

    aloxdaddy99 New Member

    I just went to do this last night. When I pulled the cover off of the fuse panel I noticed that it has HDLP RT and HDLP LT. So I tried to install the diodes to one side hoping or better yet praying that it would make at least one side work like I want (fogs on Low). No dice. I didn't want to mess anything up so I pulled the one diode out that I had installed. This was after I had to solder on a llittle piece of wire (20 gauge) to get the diode to reach to the fog light relay. Any ideas?
  19. 97killverado

    97killverado New Member

    I have a 1997 Chevy 1500 with out fogs but i am planning on installing hids, will this mod work on HIDs if not can someone guide me in the direction i need for my style truck with HID i just want highs and lows on.
  20. PantheraUncia

    PantheraUncia New Member

    This is pretty cool, but I do have question, I thought it was not "street legal" at least in NC to have additional driving lights on when the high beams were on? some how I remember people being pulled for that? but you can have as many as you want on when using low beams? Might be wrong. kinda like using HID's without the proper projector casings..... you will blind people.

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