Actually you want the rear wiper switch as that is the correct one that is an exact fit in our H2's. I have one in mine along with the extra wires but..... the BCM is not programmed for the output. Using a Tech2 I even tied the button into the correct pin and the Tech2 sees the button being pressed but the output pin does not ground out and you cannot add the programming to enable the output either.

Two options - try a BCM out of a GM truck or SUV that has the same options but also has fog lights. Needs to have the same HVAC and probably most other options.

The easiest option would be to simply get a latching relay and use the button to trigger the relay which is what I plan on doing. You can also get a latching one that does not auto-reset and then use that in conjunction with your headlight circuit so that they are always on when your headlights are on. The way the factory does it, they reset every time the vehicle is turned off so you have to push the button every time you want them on.

 

MixManSC, Very nice mod, looks clean, neat and factory. Unfortunately in the SUT they put the rear window control switch there. I also noticed on your headlight switch to holes next to the switch position, are those indicator lights and do they work?

I imagine I could relocate the rear window control somewhere else, but the question then becomes what do I do with the rear wiper control, lol I imagine there is an RPO code for the fog lamps on another GM vehicle. I don't know if the rpo code could be added to the BCM, you would also need the TIS2000 software running on a laptop, download the content, add the RPO and reflash the BCM. Seems the latching relay is a much better option.

 

Ah - did not think about that on the SUT....

Yes those are indicator light and they do come on. Never even noticed that some trucks/suv's dont have them on the headlight switch.

As far as enabling the fog light function in the BCM goes (actually GM calls it the TBCM on trucks, SUV's - truck body control module), it is a good bit more complicated than that. On a side note, we already also have the fog light relay and fuse in our fusebox under the hood too but no wiring is run. I'd have to do a good bit more digging to see what will be involved in that part. As far as the BCM programming goes when you enter in your VIN in TIS2000 it will not let you add the fog lights as they are not an option on your VIN and beyond that they are not an option on any H2. You would need a GM Techline TIS2Web subscription and than a call has to be made to the GM Techline and have them add that RPO code to the VIN. Then they give you a custom VCI number. Then in the TIS2Web SPS you select VCI programming instead of standard and it downloads the custom VCI that Techline made to program the module. TIS2Web is really just like TIS2000 and TIS2000 even has a place where you can use a VCI number for programming as well, I'm not sure that TIS2000 can still connect to GM and download custom VCI updates though. It might work though but in either case you would still have to get GM Techline to make the custom VCI number as TIS2000 will not let you add options that were not available for any given VIN number.

I have not tried it with a BCM yet but I have with a DDM (driver door module aka driver door window switches) and TIS2000 would not let me change the programming on my 2003 DDM with the programming for a 2005 one to add the global windows buttons (on the heated seat button panel on 05-07 models). Pretty annoying - I got the buttons and added them, plugged them in (the heated seats / button panel plugs into the DDM) but they did not work, heated seats did but not the global windows. With the Tech2 connected I could see the global windows buttons being pressed too. So I tried re-programming the DDM, no go as it only offered me the same software version. Next thing I tried was setting the Tech2 for programming and then in TIS2000 I put in a VIN number for a 2005 H2 (easy to find a vin # on eBay...) and it warned about VIN mismatch but still goes on. Then at the programming for the DDM it just said software not compatible with my module and would not load it. Could very well be that much of a difference between the 03/04 DDM and the newer ones but the Tech2 still was able to "see" the additional buttons and register them being pressed so I'm just not sure. I ended up buying a DDM for an 05 which was not cheap but swapped that and then the global windows immediately worked fine.

Also - for that button location. As far as I can tell, that rocker switch one is exclusive to the H2 SUT. On the Avalanche/Escalades the mid gate window does not roll down, it can only be removed. The other options for that switch spot
**** for rear wiper only. Used on SUV's.
**** for rear wiper plus fog lights button. Used on SUV's.
Fog lights button only. Used on trucks and SUV's.
Cargo and fog light buttons. Used on trucks.
Cargo lights button only. Used on trucks.
Rear window rocker switch. Used on H2 SUT's only.
Blank panel.
Small pocket.

So I think on the SUT you only choice would be to install and aftermarket switch for the fog lights, relocate the rear window switch, or possibly if you do not have the factory air ride you might be able to get a factory push button for the blank button panel in the center stack where the rear air ride button would go and use that for the fog lights. On those center stack buttons, there are a variety of other factory ones used on the GM Trucks and SUVs in a 4 spot section of the dash with various functions as well.

 

MixManSC, I wasn't aware there was a lock out on adding RPO codes that were not built into the profile for a specific vehicle. A number of years ago I deleted the magnetic suspension code on my 03 Corvette but I guess that worked out ok because it was a deletion and not an addition of a code not specific to that model. Not only that I have no access to the GM database anymore so for all practical purposes that a dead end.

Your idea of adding an aux switch is probably the best one for my circumstances, I have the air suspension so I cant use that spot. I think what I will do is pull pin B4 from BCM connector C2 and run that to the switch. All I would need to do is simply ground the lead and bingo, switch controlled fog lamps or installed a self latching relay. Since the original circuit is ignition powered even if I forgot and left the switch on the lamps would be off with the ignition

I have already temporally pulled the DRL relay and will watch for any codes but I doubt the BCM will generate any. The only way I could see it would is if the BCM monitors B4 for a floating voltage and could detect a pulled/blown fuse or a missing relay.

If the BCM throws a code another wiring alternative would be to pull the lead directly under the fuse block on pin B2 of connector C4 and supply 12v through an aux relay wired back to a switch.

Another bit of info, the headlight switch mod does not work as advertised, even it the light switch is left in the off position the DRL's still come on when the vehicle is placed in drive. Apparently the circuit wants to be pulsed to ground as if the driver rotated the switch from auto to off and released for the DRL's to actually be disabled. So for all practical purposes the headlight switch mod is useless as I see it.

BTW, it that headlight switch the original that came in your H2 or did you add it. I like the indicators and would like to find that same switch. Knowing GM they probably found a way to make a cheaper switch and deleted them for 06 and later. lol

 

I'm honestly not certain if that one is the original or not..... I have an extra laying around and when I modded it to be red lighting (note that the dimmer icons on the right side also light up - those normally do not) I cannot remember if I just modded the one I had laying around and stuck it in or pulled the original and modded it. I'll take a look in the morning when I head into the shop and peek at the one I have in there. I'm also now not certain that those light up so I'm going to have to double check as I've never really even noticed that it has those while others do not. Since you mentioned it I see both on eBay (I'd still double check with a seller if it is a multiple available type listing to be sure that is what you would actually get). I got a little more curious and narrowed an eBay search using this

2003 silverado headlight switch -2006 -06

Then looked at listings where they specifically state that it came from a 2003 and all appear to have those extra led's while the same specific search on later models, none have them. So I'm guessing that was a one year only thing - my H2 is a 2003...

 

MixManSC,

I found one on eBay with the indicators, if you have a chance and can check let me know if the indicators do in fact light up when the headlight switch is set to that specific function,

I dont plan on purchasing another if they don't
Thanks

 

They do - not super bright but they do light up. Top is with headlights on. Bottom one is amber and is after I rotate the switch to off once to turn the headlights off...

 

Thanks MixManSC, I appreciate you checking that for me, I am going to pick up the one on ebay auction. I want to replace my current one anyway, as since the "OFF" mod doesn't work right.

 

I believe 2003 was the only year for those indicator lights. It's inclusive into the switch so the switch manufacturer made that change at some point during the 2003 and perhaps 2004 model years.

 

clsimmon, I believe you are correct on this. Checking with GM there was a part number change for the headlight switch that happened mid production. My guess is manufacturing cost for deleting those indicators were enough to justify GM doing it. Especially when you consider that particular switch was used in the SUV's, Trucks along the GM line. Bean counters strike again, lol

Anyway, I wanted to share a little more about the headlight switch mod. Don't was your time with it. Apparently the person that came up with it and originally posted it on one of the truck forums did not fully test it.

Here's the results, if you leave the switch in the off position you will still need to pulse the DRL circuit to ground in order to trigger the circuit to release the DRL relay. Add to that if you leave the headlight switch the off position the BCM will detect the switch is not in an auto position and generate a DTC, it won't illuminate the check engine light though. Other then disabling the autolighting control modifying the switch to allow it to remain in the off position is for the most part useless. Bottom line the best solution to using the DRL's as fogs would be to relocate the bulbs themselves to another location and connect them to perhaps 168 bulbs to satisfy the circuit and the BCM and putting in a relay controlled switch in the cab and using different bulbs in the enclosure. This way you have full functionality, won't cause any codes and will not waste the enclosures for something as useless as DRL's